Easy to install and operate TPMS for your 6 wheel truck or RV. Sensors are heavy duty to handle heavier vehicles for up to 188 PSI of pressure. The default alarm setting for this model is 80 PSI for low, and 120 PSI for high alarm. Can be changed easily in less than a minute. Sensors operate on exchangeable watch batteries (CR1632). Average life of 2 years (depending on how long the vehicle is in motion). Display with built-in rechargeable battery, can be charged while operating via solar panel on top of the unit as well as mini USB port for faster charging requirements. Main unit: 5" wide by 1.5" high and 2.5" deep. Sensors: 0.9" round with 0.7" thickness, 0.4 OZ each