A sturdy metal hook (approx. 10-23 cm) with a wooden, bone or metal T-handle (sometimes a ring, see boot jack) with which to put on high boots. Sometimes a button hook and a punch were forged on the end of the T-handle (1).
The boot hook is inserted into the strap that is attached to the top of the boot; then the foot is put into the boot and the boot is put on. When the boot has two straps, two boot hooks can be used.
The hook may have a decorated shank or a spherical button on the end to prevent the hook from slipping out of the strap; some are foldable.
A boot jack can be used to take off boots easily. [MOT]
(1) David Stanley Auctions. 65th international auction 28th March 2015: 11.