This complete replacement upper thread tension assembly (part # 44118) is designed for Singer Industrial sewing machines. The assembly comes ready to install with the release pin included, providing precise thread tension control for professional industrial sewing applications. Specifications: Part Number: 44118 Type: Replacement (aftermarket) Barrel diameter: 17.4mm Includes release pin Complete assembly ready to install Compatibility: Fits Singer Industrial models: 31, 31-15, 31-17, 31-18, 31-19, 31-20, 31-29, 16-188, 17-41, 42-1, 42-2, 42-3, 42-4, 42-5, 42-8, 43-1, 43-2, 43-3, 43-4, 43-5, 43-6, 46K5, 44 class Important Note: Some models may use a different barrel diameter depending on the year of manufacture. Please measure your machine's tension assembly opening before ordering to ensure proper fit.