The SMAI Swivel and Chain can be used with almost any punch bag as an extension to the product. SMAI recommend that the swivels be used on all bags as it reduces the wear on the straps and D-shackles by allowing a free range of movement. Specifications Material: Steel with welded chain Max. bag tolerance: 60kg (Standard) 40kg (Small) Standard Chain length: 50cm Small Chain length: 40cm