3/32 or 1/8" chains will work fine. Freewheels have notoriously been considered the Achilles' heel to the drive train system. Traditionally, the freewheel has been considered a disposable component that should be replaced on a regular basis. We approached the component differently. We set out to create and manufacture a freewheel that would be durable, reliable, and easily maintained. We succeeded in our endeavors and the ENO freewheel is now regarded as an industry leader. The freewheel utilizes a sealed cartridge bearing instead of a loose ball system. The advantage of the cartridge bearing is that it is sealed from the elements such as mud, grit, and water. The other benefit is that the bearing is nicely contained in one simple unit and easily pulled and replaced when worn. The ENO freewheel features a machined inner driver and machined outer gear case resulting in a freewheel that runs concentrically without the tight loose spots common to other freewheels. 36t engagement system and a case hardened, electroless nickel plated outer gear case make this freewheel a perfect addition to your single speed. Made in the USA