Originally it was a roller skate or skate board wheel. Comes with bearings. This will keep your chain from hitting your bike or swaying all over the place. Bike chain will roll over this idler smoothly and quietly. Spinnies come in bright color combinations.
Styles are light weight and made of black canvas type of material.
Each bag has pockets. Available with integral Hydro-Pack water bladder. Easily attaches to seat back. The bag includes two external water bottle holders, and external zippered pocket and a large waterproof carrying compartment. Internal divider pocket, small exterior zippered pocket.