sentences:  Since at least 2007, Rollerblade brand amongst others have begun using their own rating system.For instance, Rollerblade brand is currently using a SG1 to SG9 rating system, whereas TwinCam brand is using its own "ILQ" (InLine Qualified) rating system and Bones brand is using its own "Skate Rated" rating system.A mistake that is often made in purchasing bearings is that spending more translates to more speed.