The Britton Lens Tube Spacer is designed to maintain a fixed distance between two SM1-threaded optical components, making it ideal for extending optical paths and creating modular optical assemblies. Featuring external SM1 threads on both ends and a large clear aperture, it ensures easy integration with lens tubes, mounts, and other SM1-compatible components. The robust black anodized aluminum construction provides durability and minimizes unwanted reflections in optical systems