Color denotes(demotes?) strength and/or toughness of the pipe. White is thin and more plasicy, good for protecting cables and shit, not for skiing. Black is the opposite, it is significantly harder, and chips instead of taking off shavings, is very thick and is used for plumbing and shit. Grey is kinda the 'happy medium',its plastic-y but thick enought that you can jump on it and it wont collapse. its what we used for our jibs andI is perfect. We tried black but it was too easy to catch edges, and instead of just taking out a chuck of plastic, we would fall. So basically, Grey>black>white