2-stage head to provide better sealing than lever chuck designs- Machined aluminum head, barrel, handle and piston rod- Leather piston gasket- Brass check valve- FlexWing silicone bumpers on the head and handle tip are designed to accommodate frame tubing diameters from 1" (25mm) to 2.5" (64mm)- Bumper on the main barrel protects paint, eliminates vibrations and noise, and acts as a handle lock- Adjustable fit to fine tune the length for additional security for all top tube lengths- 256g-289g