Green’s Dictionary of Slang

cramp-rings n.

also cramping-rings, queer cramp-ring
[SE cramp: a small iron bar with its ends bent into hooks + ? pun on the orig. 15C SE cramp-ring, a ring worn on the finger to ward off cramp, epilepsy etc + queer adj. (1)]

[mid-16C–mid-19C] (UK Und.) shackles or fetters.