There's two types of shackles: a bowshackle and a D-shackle, both available at Mennens. A bowshackle allows more movement than a D-shackle. The choice between a shoulder bolt or nut bolt depends on its use. If it's necessary to remove the shackle on multiple occasions, a shoulder bolt is your best option. For a semi-permanent link, a nut bolt will suffice. Not sure which type you need? Don't hesitate to contact us for help, we're here for you.