1、T6 heat treatment, full CNC machining, frosted polishing, anodized. 2、Lightweight aluminum alloy design, frosted polishing, precise wire cutting, closed loop full occlusion, not easy to slip teeth, and will not damage the bottom bracket. 3、Used for bicycle underframe maintenance, with special professional design. 4、Light weight and portable, easy to carry and use. 5、2 different types for you to choose, meet your different needs. 1 x Bike BB Wrench Item type: Bike BB WrenchMaterial: aluminium alloyColor: As picture shownWeight: Approx. 64g Tool-A: Suitable for bottom bracket with an outer diameter of 44mm/ 1.7in and 16 tooth space. This model is the most common bottom bracket specification. (for BB51/for BB52/for BB70/for BB71BBR60/for MT800/for RS500/for MT500, etc.) Tool-B: Suitable for bottom bracket with an outer diameter of 46mm/ 1.8in and 24 tooth space. (for BBR9100/for XTR/for DA/for SxAM/for DUB etc.)