In Ring Spanner, the jaws form a ring with internal serrations which fit completely around a nut, usable in confined spaces.It has rings at both ends which fit easily into the nut or the bolt head,as a ring would fit a finger.Hence you can see that the fitting feature of this spanner is same to that of a box.The length ranges from 170mm,182mm,195mm,212mm,225mm ,they are used for fitting,assembling operations to screw and unscrew.

In Ring Spanner, the jaws form a ring with internal serrations which fit completely around a nut, usable in confined spaces.It has rings at both ends which fit easily into the nut or the bolt head,as a ring would fit a finger.Hence you can see that the fitting feature of this spanner is same to that of a box.The length ranges from 170mm,182mm,195mm,212mm,225mm ,they are used for fitting,assembling operations to screw and unscrew.