Metal Construction : Aluminum alloy for superior strength, smooth threading, and long lasting performances without deformation or stripping Anti Wear & Securely Fit : Resists to rust, while tightly threaded engagement prevents loosening, chipping, or wear over time precise Alignment : Features a flat end texture for even pressure and high concentricity, stabilizing the shaft to prevent image misalignment Wide Compatibility : precise engineered to pair for Copal Compur Prontor number 1 shutter specifications, ensuring seamlessly fit with most large format lens boards and barrels for convenient use Safe Installation & Removal : High precise threads enable smooth mounting/dismounting without damaging shutter hoop or lens mounts, ideal for maintenance