This is a precision-engineered 3D-printed power coupler. It's built to manage normal-to-heavy loads while functioning as a fail-safe under extreme stress, safeguarding your equipment. Length is 3.75” Made from a tough, high-performance polymer material, it delivers outstanding strength for everyday applications and is precision-designed to shear safely during overload—just like the original intent—to avoid harm to your tools. Both ends of the coupler are compatible with the splined metal hubs found in Shopsmith setups, guaranteeing seamless compatibility with MARK 7, MARK V, MARK 4, Power Station, and specialty tools such as bandsaws, planers, jointers, and beyond. ⚠️ Note: Engineered for dependable operation in tough scenarios, this part is intentionally designed to shear under severe overload, protecting your machinery from damage.