Very interesting. PVC is white, ABS is black, but as you point out, the white fitting you have says ABS so ???. PVC and ABS are different chemically and require different solvents ("cement") What presents a problem is that neither of these so called "cements" are glue or cement. They are solvents that melt the top surfaces of the fittings and pipes so they actual form a weld when jointed, and since PVC and ABS are different chemically, you don't mix and match the solvents. There is a product that will work on both PVC and ABS, but you must be certain that you get the right thing. I know of no yellow "cement", but perhaps it is for CPVC that is used for interior water supply lines It should say what it is for on the can.