It is a tube form composed of fine weave cotton cloth reinforcement combined with a phenolic resin system. RTB320 meets the requirements of MIL-I-24768/13, Type FBE and is designed for electrical and mechanical applications that require fine machining. RTB320 offers low moisture absorption and excellent dimensional stability. It is suitable for cams, gaskets, rings, collars, sleeves, brake lining, timing wheels, and hydraulic rings, light duty gears, bearing retainers, bearings, and thrust washers. A variation of this grade comes heat treated in an oven (H) for increased dimensional stability.