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