The precision-engineered Wolf Tooth Seatpost Clamp secures your seatpost and looks good doing it. At the heart of this seatpost collar are our custom self-aligning bolt and anchor. The M5 bolt includes spherical washer and mates with a cylindrical anchor barrel. This means that threads are always perfectly aligned, preventing binding and ensuring consistent clamping force. Machined from 6061 aluminum in our Minneapolis facility, the Wolf Tooth Seatpost Clamp is available in seven sizes with the Raw Silver anodized color. Compatibility Clamping Diameter - 28.6mm/29mm - 29.8mm/30mm - 31.8mm/32mm - 34.9mm/35mm - 36.4mm/36mm - 38.6mm/39mm - 39.7mm/40mm Frame size may vary slightly from the nominal diameters due to tolerances and paint thickness. Clamps will fit on frames that are within +/- 0.5mm of specified size. For example, a 34.9mm clamp will fit frames with a seat tube measuring from 34.4mm to 35.4mm in diameter. Clamp height: 13.5mm - Not compatible with Ibis carbon bike frames.