TPMS Tyre Pressure Monitoring System Caravan Truck RV Sensor LCD 4WD Wireless 4x4

Display Real-time Critical Tyre Information on your Dash

RRP $238.05
SAVE $11.05 (5%)

Item Number: TP-21SI

In Stock

The Masten TP-21 TPMS Tyre Pressure Monitor System with Premium Long-Life Internal Sensors is specifically designed for for those wanting to monitor their tyre pressure in a non-obscure way due to the compact design of this monitor.

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IMPORTANT - This Listing includes everything you need to monitor the condition of your tyre pressure and temperature. It includes the following parts:

  1. Masten Real-Time TPMS 3.5" Monitor with Upgraded Transmitter and Improved Brightness Panel x 1
  2. Premium Masten TP-09S Internal Valve Sensors x 4
  3. Weather-proof Rubber Seals -fitted
  4. Cigarette Socket Power Adapter x 1
  5. Desk-Mount Monitor Holder Attachment x 1
  6. Windscreen Suction Mount x 1
  7. Optional - Masten TP-09REP Range Extender

Spare Sensors:

If you're after spare sensors the part numbers are TP-09S (internal valve) and TP-10S (external cap)


Towing? This clever monitor allows you to 'un-link' when you are not towing so you wont have the monitor beeping while worried about lost sensors. 

Instructions: When the trailer is not connected to the main vehicle, press the LINK and - buttons at the same time. The trailer and its tire icons will be removed temporarily. Press the LINK and + buttons at the same time and the trailer and its tire icons will re-appear. Clever, HUH!



The Masten TP-21 TPMS Tyre Pressure Monitor System with Premium Waterproof Internal Sensors is specifically designed for for those wanting to monitor their tyre pressure in a non-obscure way due to the conpact design of this monitor.

Key benefits of the TP-21 Masten TPMS

  1. Upgraded 8m Singal Strength compared to similar models (with optional TP-09REP Masten Range Extender you'll get 200m Range - line of sight)
  2. Improved Screen for greater visibility with intense sunglare with Automatic Backlight
  3. Monitors up to 22 Tyres
  4. Built-in and Rechargeable Lithium Battery with up to 60 hours charge
  5. Configurable high and low pressure and temperature warnings
  6. Fast Leakage Alert
  7. Anti-theft Sensors
  8. Pressure Range of 0 to 8 BAR (with ±0.1BAR Accuracy) and 0-116PSI  (with ±1.5PSI Accuracy) -
    1. For greater pressure ranges (0 to 13 BAR / 0 to 188PSI) see the TP-20 model
    2. Note, this TPMS is also compatible with spare sensors TP-09S Internal Sensors, TP-10S External Sensors and TP-20S External Truck/Caravan Sensors

The TPMS module works silently and alerts you if there is a problem with your tyres. The Tyre data can be viewed at all times. 

Feature List:

  • Professional Installation Required
  • Masten improved wireless signal
  • Attractive design with visual and audible alarm
  • 8 Metre Wireless Range
  • PSI and BAR Adjustable Units
  • Adjustable Front and rear sensors high/low pressure alarm range
  • Real-time Tire Pressure and Temperature Display of all Tyres Simultaneously
  • TPMS information screen will automatically appear if a tyre problem is detected
  • The clear display allows you to easily identify problem tyres in red for fast evaluation
  • Premium quality sensors
  • Up to 5 Year Battery Life
  • User friendly programming functions

Overview of TPMS Monitor and Sensors

  • Monitor Tyre Pressure and Temperature on your Car, Truck, Trailer, Caravan, Horse Floats Continuously in Real-time
  • The Masten TP-21 Monitor produces an audible alarm when the pressure drops below or rises above your preferred set ranges
  • We have options available for 4, 6 and 8 sensor kits – the TP-21 will pair with up to 22 tyres and we offer spares at an extra charge
  • Easy to use monitor with a simple switch function allowing you to switch off caravan/trailer sensors when it’s parked 
  • Audible alarm when monitor or sensor batteries are running low
  • Included Cigarette Socket Charger and hard wire cable for concealed power

Sleep Function:

If the sensors have not been moved for 1 hour or more they will be in sleep mode. After around 5 seconds of movement the sensors will 'wake' up and start sending the tyre information data (pressure/temperature) every 6 seconds to the monitor.

User Manuals comes in the box for unit and sensors: E-Copies also available from us. 

We have instructionals on our youtube page also if you are having difficulty installing. 


Optional Accessory - Masten Range Extender



What are Tyre Pressure Monitor Systems?

passenger vehicles in the 1980s and today is a mandatory feature in the United States. 


Benefits of a Masten TPMS?

The dynamic behavior of a pneumatic tire is closely connected to its inflation pressure. Key factors like braking distance and lateral stability require the inflation pressures to be adjusted and kept as specified by the vehicle manufacturer. Extreme under-inflation can even lead to thermal and mechanical overload caused by overheating and subsequent, sudden destruction of the tire itself. Additionally, fuel efficiency and tire wear are severely affected by under-inflation. Tires do not only leak air if punctured, they also leak air naturally, and over a year, even a typical new, properly mounted tire can lose from 20 to 60 kPa (3 to 9 psi), roughly 10% or even more of its initial pressure.

The significant advantages of TPMS are summarized as follows:

Fuel savings: According to the GITI, for every 10% of under-inflation on each tire on a vehicle, a 1% reduction in fuel economy will occur. In the United States alone, the Department of Transportation estimates that under inflated tires waste 2 billion US gallons (7,600,000 m3) of fuel each year.

Extended tire life: Under inflated tires are the #1 cause of tire failure and contribute to tire disintegration, heat buildup, ply separation and sidewall/casing breakdowns. Further, a difference of 10 lbs. in pressure on a set of duals literally drags the lower pressured tire 13 feet per mile. Moreover, running a tire even briefly on inadequate pressure breaks down the casing and prevents the ability to retread. It is important to note that not all sudden tire failures are caused by under-inflation. Structural damages caused, for example, by hitting sharp curbs or potholes, can also lead to sudden tire failures, even a certain time after the damaging incident. These cannot be proactively detected by any TPMS.

Decreased downtime and maintenance: Under-inflated tires lead to costly hours of downtime and maintenance.

Improved safety: Under-inflated tires lead to tread separation and tire failure, resulting in 40,000 accidents, 33,000 injuries and over 650 deaths per year. Further, tires properly inflated add greater stability, handling and braking efficiencies and provide greater safety for the driver, the vehicle, the loads and others on the road.

Environmental efficiency: Under-inflated tires, as estimated by the Department of Transportation, release over 57.5 billion pounds of unnecessary carbon-monoxide pollutants into the atmosphere each year in the United States alone..

  1. 6 Good Reasons to Install a TPMS

    1. Prevent tire puncture

    When the tire is high or low, or high temperature, the system will send a trigger warning in time to reduce the puncture possibility

    2. Tire leaking warning

    When the tire is leaking, the system will immediately send a trigger warning

    3. Reduce tire wear

    It will accelerate tire wear when the tire pressure is too high or too low. Keep the tire pressure correct to extend tire life.

    4. Tire balance

    Vehicle deviation will easily occur if tires are unbalanced. Maintain the pressure balance of the 4 tires to improve vehicle handling and shorten the braking distance

    5. Save fuel

    When the tire pressure is low, the fuel consumption will be increased due to the high rolling resistance of the tire.

    6. Govenment Legislation

    In 2007 the US government legislated the mandatory installation of TPMS to new vehicles. 

    In 2012, 27 countries in the European Union plus Japan and Korea legistalted the mandatory installation of a TPMS to new vehicles. 

    In 2016, China, Australia and several South East Asian countries will legislate the mandatory installation of TPMS to new vehicles. 


  2. Color LCD display.
  3. Pressure and temperature alarm.
  4. Visible and audible alarm.
  5. Selectable pressure units: BAR or PSI.
  6. User programmable alarm condition.
  7. Tire position swapping.
  8. User dimmable backlight on display.
  9. Supports up to 5 tire (including spare tire).
  10. Fast leakage alarm.
  11. Easy installation, stable performance.
  12. Human icon as car load adjustment
  13. Tire pressure reference indication.
  14. Real time tire pressure drift data.
  15. Temperature reference indication.
  16. Tire temperature indication.
  17. Half load and full load alarm setting.
  18. Display pressure or temperature of four tire at the same time.
  19. Separate front axle and rear axle alarm setting.

Monitor Specifications

Operational Temperature: -20 to 80°C

Storage Temperature: -30 to 85°C

Transmission Frequency: 433.92MHz

Charger Input Voltage: DC 8 to 30V

Size: 116(L) x 68(W) x25 (H)mm

Weight: 138g


Internal Valve Sensor Specifications - Optional

Operational Temperature: -40 to 80°C

Storage Temperature: -40 to 85°C

Pressure Range: 0 to 8BAR, 0~116PSI

Pressure Accuracy: ±0.1BAR, ±1.5PSI

Temperature Accuracy: ±3°C

Transmission Power:<10dBm

Transmission Frequency: 433.92MHz

Battery life: Up to 5 years

Size: Size: 60(L) x 35(W) x21(H)mm

Weight: 48g

Barcode # 2000000002750
Brand Masten
Shipping Weight 0.6000kg
Shipping Width 0.280m
Shipping Height 0.080m
Shipping Length 0.200m
Assembled Width 0.280m

2 Year Warranty

1 Year Warranty on Sensors



Changing the Pressure Alarm Ranges

Our TP-19 and TP-20 monitors default alarm settings are as follows:

  • High pressure: 175PSI - NOTE. the Minimum Alarm Range for these models is 3PSI.
  • Low pressure: 100PSI

If you need to re-set the high pressure alert range below 100PSI and find the high pressure setting range is from 100PSI to 218PSI (due to the low pressure setting max. data is 100PSI). This is normal. You will need to set the low pressure first, and then the high pressure again, for example, please set the first axle 1 low pressure to 30PSI, and then set axle 1 high pressure, the high pressure setting range for the axle 1 will be from 32PSI to 218PSI. 

Due to the caravan pressure alert range usually from 30PSI to 50PSI. So please re-set the low pressure of all axles to 30PSI and then scroll to re-set high pressure to 50PSI again. 

Normal re-setting step as below:

  1. Turn on the monitor.
  2. In normal mode, press the SET button for 3 seconds. You will hear a beep when you release.
  3. Press the SET button to scroll through the different settings, the sequence is pressure unit, temperature unit, axle 1 two tires high pressure, axle 1 two tires low pressure, axle 2 four tires high pressure, axle 2 four tires low pressure, axle 3 four tires high pressure, axle 3 four tires low pressure, trailer axle 12 tires high pressure, trailer axle 12 tires low pressure, all tires high temperature.
  4. Press the + or - button to change the setting data.
  5. Press SET button for 3 seconds with a beep to save the new setting.

If you want recover to the default setting, press and hold the SET button without release, then turn off the switch and turn on the switch with a beep. Default setting is restored successfully. 

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