Made of high density polyethylene will not rust, corrode or cause nipples to rust material tested to minus 40°f will withstand harsh chemicals and oils when bent or crushed will spring back into shape leaving no permanent damage weep holes at bottom designed to keep nipples out of water 1/2" caddy; holds 77 pipe nipples, 7-1/2" x 11-1/4" x 7" 3/4" caddy; holds 66 pipe nipples, 8" x 13-3/4" x 7".