What size chain fits an Oxford Boss lock?

Updated on Mar 17, 2026

Oxford Products make a range of locks called Boss.

The range includes disc locks and chain locks and varies in shackle thickness.

The thickest shackle on an Oxford Boss lock is 16mm and the thinnest is 12.7mm.

The aperture of the lock (the space within the shackle) is a minimum of 41mm x 51mm.

These locks can accommodate Pragmasis chains up to 19mm in thickness. Our Protector 19mm chain for example. Although you may find a better idea is to match the shackle thickness with the chain thickness, so that there's not one obvious target. Therefore we'd recommend a Protector 16mm chain to go with the thickest Oxford Boss lock.

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