They can be used on cars and trucks. I've had one for years but have not had the need to use it yet. I did notice the motor oil had leaked out of the bottle in the kit. The mushroom plug needs oil for lube. I decided that a drip from the dip stick would be enough not to need this leaky little bottle.I saw the mushroom shaped jobbies at a camping/fishing expo. They were demonstrating them on a motorcycle tire, and an atv tire. Maybe they aren't for truck tires? Dunno.