Aqua-Proof Roller Chain BS | Single Pitch | Anti Corrosion | AP “AP” type roller chains comply with the RoHS Directive. Its corrosion resistance is far superior to nickel or zinc plated chains, yet it maintains the strength and durability of the SUGIYAMA carbon steel roller chain. “AP” type roller chains are the perfect choice when both corrosion resistance and high strength are needed. Average Tensile Strength The thickness of the intermediate plate of the multiple strand 08B AP chain is 1.25mm. Connecting links are “cotter” style for size 16B-3 AP and all sizes above 20B AP. Takes account of a 35% reduction of fatigue strength when a single pitch offset link is used. Do not use Aqua-Proof chains in applications where chain may come in direct contact with food or where coating flakes or wear dust can contaminate food.