As part of their continuing quality improvement program, the RK Chain Factory has made a running production upgrade to their best selling 428XSO chain. The new upgraded 428XSO chains feature heat treated hi-carbon alloy steel components with seamless rollers and shouldered bushings, and are fitted with RK's proprietary RX-Ring seal design. RK's new 428XSO chains offer quality, performance and unbeatable value, for all but the most demanding high performance application. RK's RX-ring chains feature an X-ring shaped seal. Viewed in cross-section, the X-ring has two lubrication pools and seal points versus the single seal point/pool design of a regular O-ring chain. RX-ring technology offers less torsional friction, increased high-stress performance, and a 30% longer wear life compared to standard O-ring chains. RK's new RX-ring chains offer tremendous value, plus true quality and performance for all but the most demanding high performance applications. Pin Length in mm: 21.8mm. Plate Thickness: 2.0mm inner & outer. Maximum Tensile in lbs./Ft: 5,280 lbs./ft. Master link Type: Clip/Rivet. Weight in Lbs. per 100 Links: 2.65lbs. Max cc: 400cc Street / 350cc Off-Road.