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 6708

17t- 23t:  red locking ring, designed for 3/32 chain will also accept  1/8 chain, bearing size 6808