I had a Tyre Dog TPMS on Bo , but don’t like the valve cap sensors. So I bought the an Aleen 509 solar unit to test on the Colt first.

Click on any pic for a larger view

I  ordered it with 5 internal sensors

Sure you need to have them fitted by a tyre fitment place , but once that is done , they are totally unobtrusive and it is very easy to reprogram the receiver whenever you rotate wheels

The receiver comes with a 12v cable , but I have found that the smallest amount of exposure to sunlight will give the unit enough charge to operate without ever needing the 12 v supply

The display rotates between the 4 main tyres and the spare , and you can also display the temperature .

There are user selectable settings for Bar/PSI , C/F and you can set maximum / minimum pressure warnings per axle , as well as maximum temperature

I ordered my unit online from Dawood at Tyrealert and it was delivered within 2 days.

He also has a range of other options available.