KMC 1/8" half link
$ 3.99
This extremely handy little dandy will add or subtract 1/2 a link (1/2") from your chain, allowing you to move the axle 1/4" forward or backward to dial in chain tension or slam that rear wheel.
Available in two versions - black works with all standard 1/8" KMC chains (S1/Z410), silver works with K1 Wide and K1SL Wide chains.
The standard (black) version is also compatible with Izumi 410 ECO and Miche 1/8" track chains.
• for use with 1/8" chains only