Function: Rear chain block can adjust the rear wheel chain to help you adjust the tightness of the chain. Appropriate tightness can not only reduce wear between gears and chains, but also prevent chain shaking and even detachment.
Aluminium Alloy: Sturdy and Lightweight.

Specification:
Item Weight: 318g.
Item Size: 18 X 10 X 3 cm.
Service: If you have any questions, have time to tell us and we will do our best to answer your questions.

Package Includes:
1 Pair Chain Tensioner Adjusters, as pictures.
Instruction of Installation is NOT Included.