Designed to open the Rolex™ Oyster style case backs.
Comes with 6 rings in sizes:
18.5mm, 20.2mm, 22.5mm, 26.5mm, 28.3mm, and 29.5mm.
The rings are precision made to interlock so there is no slippage. Its sturdy aluminum frame fits into your bench vise and the turning bar provides the torque you need to open stubborn backs.
Be sure to measure the diameter of your watch. Some Men's watches on the market today are much larger than the largest ring.