Threads: 1.375” x 24TPI All freewheels are 18.4mm wide: On ENO single freewheels (standard and discontinued Trials) center of teeth are 9mm from the inner base of the threads On ENO DOS double freewheels inside teeth are 6.1mm from the inner base of the threads and the outside teeth are 11.8mm from the base. Teeth are 5.7mm apart center to center White Industries now offers all freewheels with the High Engagement option that used to only be available on Trials freewheels. These no longer use the thicker outer gear case that was a feature on Trials freewheels as we deemed it an unecessary cost and weight. The standard outer gears are tough enough! Standard Engagement freewheels have 3 pawls and 36 points of engagement High Engagement freewheels have 6 pawls and 72 points of engagement 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. We no longer offer the green Trails lockrings which were specific to Trials freewheels. All White Industries Freewheels are Made in the USA!