These BMW R100 / R80 (and other R series models) YSS suspension replacement rear shock absorbers from the Topline range, are a high efficiency gas shock absorbers that can be adjusted according to the user. There are 4 main features to this shock: 1. It has a threaded preload adjuster which the user can turn in order to personalize their setting. 2. It has rebound adjustment. 3. It has length adjustment of /- 5mm. 4. The shocks are completely serviceable. There is also the option to fully customise the look and length of your BMW R Series shocks in a number of ways via our partner in Netherlands – YSS Suspension Store. Check out the options below: YSS recommends Bobber conversions at 420mm lengths; however, you have the option to select shorter or longer options according to your needs. Note that each shock is custom built to your specification and takes about 10 business days to process.