[Cavalier2000]

I can't remember what they are called, but you put it on the collant tank and then use an air compressor to suck all teh collant out of the car and the hoses actually suck down, then you close the valve and if the system fills back up with air then you have a leak, if it doesn't then you connect a line full of collant to the sucker thingy and realise the valve and it pushes all teh collant into the system with 0 air. it's neat thingy to have