X101: high-performance, chamfered, anti-drop, lightweight, Singlespeed chain for Mountain, BMX, Fixie, Track applications S10: stainless steel construction great for electric bikes, internal gear hubs, and beach cruisers K1 Wide (formerly Z710): specially shaped, extra-thick outer plates and bulls-eye riveting for frequent grinding S1 (formerly Z410): bushing-less design for normal BMX and Singlespeed use B1H: nickel plated chain has heavy duty structure with bushing construction Z1eHX: heavy duty chain has gone through a stretch proof treatment and features mushroom riveting along with an antidrop design