Check the listing for details. WHITE Industries ENO Freewheel 18 t - sealed bearing free wheel. Condition: New. Listed at 115.90 USD. The ENO is the answer.The freewheel utilizes a sealed cartridge bearing instead of a loose ball system. There are two advantages to the cartridge bearing: It is sealed from elements like mud, grit, and water.The bearing is nicely contained in one simple unit, 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 and loose spots common to other freewheels. A 36 point engagement system and a case hardened, nickel electro-plated outer gear case make this freewheel a perfect addition to your single speed. For trials riders or those wanting a beefier version we offer the trials freewheel with 72 points of engagement and a thicker outer gear case to withstand the rigors of a more demanding style of riding.Sizes:16t: blue locking ring, accommodates 3/32 chain only, Bearing size 670817t- 23t: red locking ring, designed for 3/32 chain will also accept 1/8 chain, bearing size 6808