jatech Heavy Duty 520H 520 Chain Connecting Master Link W/O-Ring Seal for Motorcycle Dirt Bike ATV Quad Gold 520H Duty Chain Joining Connecting Master for Links w Fitment: This chain is suitable for 520H Chain Motorcycle Precise Forging process leads to a stiff chain for better acceleration and more efficient engine work. Lightening hole allows for a lighter chain without compromising strength while removing mud and dispersing heat more efficiently. Improvement in transmission efficiency. Special pin with holes in both ends allow the chain to be lightened