Shoof's self-piercing 8 mm stainless steel bull rings last longer on hard ground and are proven to be reliable. The locking pin is thumbscrew-type and breaks off when tight, revealing a cross-slot for screwdriver. Three sizes available: small 64 mm, medium 70 mm, large 76 mm outer diameter.
Hayes Veterinary own-brand self-piercing stainless steel bull rings. Longer lasting than copper especially on hard ground. Proven in use. Thumbscrew-type locking pin, broken off when tight, reveals cross-slot for screw driver. Dimensions are o.d.