General Specifications for NRG COMPANY, INCORPORATED Rectangular Clarification Equipment Part 2 - Products 2.11 Drive Chain   Drive Chain shall be non-metallic NH78, 2.609" pitch, glass-reinforced nylon as supplied by NRG Company, Inc. The chain shall have a rated working load of at least 1750 #. The connecting pin shall be 7/16" diameter stainless steel with 1/8" diameter cross pin of stainless steel.