Steel rings from ISC are rated to 70kN and are fully marked. Made with 11mm bar stock, these things are practically bomb proof.

Available in two sizes.

Small Ring:

Internal Diameter = 27mm (1 1/8")

Outside Diameter = 51mm (2")

Large Ring :

Internal Diameter = 45mm (1 3/4")

Outside Diameter = 70mm (2 3/4")