The fiber mounting 2-piece ladder rack bracket attaches to either a 3/8" (9.5mm) wide x 1 1/2" (38.1mm) or a 3/8" (9.5mm) wide x 2" (50.8mm) ladder rack rail. The bracket halves slide into position and clamp together on the ladder rack rail, which allows for one-handed assembly of the 5/8" threaded rod (not included). It contains the bracket and hardware for attaching the bracket to the ladder rack. It is black and made of steel. F2PCLB58 BRACKET ADAPTER LADDER RACK TO 5/8" ROD