What is the Mini-Miser? The Mini-Miser is a revolutionary new ultralight bearing upgrade system. It utilizes a skate bearing unlike any you have ever seen. The overall bearing weight is reduced almost 70% compared to the industry standard conventional 608 skate bearings. To use the Mini-Miser system, a skater first buys the Upgrade kit (16 or 20 pack for inline). The upgrade kit consists of 16 or 20 bearings, 16 or 20 precision machined acetal (aerospace grade nylon) sleeves, and 8 or 10 precision machined aircraft grade aluminum, self-centering spacers. Once the initial kit is purchased, then thereafter the skater must only buy replacement Mini-Miser bearings, as the durable sleeves and spacers can be easily transferred between sets of wheels.