We've always been a fan of color coded products to identify the different properties of each.  These rubber grommets by IST are colored to the tension varying from 25 to 45.  The higher the number, the more resistance

Compatibility

These rubber grommets are compatible with their Myoungshin Fanta / Fujin / Alpha and Knee Levers

Quick Link:  https://tinyurl.com/ISTGROMMETS