The steel parallel set to use in the precision position of workpiecs. Econo mical, Simple and easy to use in precision clamping of parts indrilling boring, milling, prinding, assembly work, etc.Thin parallel bar set's top and bottom surface is precision ground to .0002'' flatness.Easier handling because there are 2 holes in each parallel. combo set, 10 matched Pairs.All the size are 6'' long and 1/8'' wide or thick.Includes 10 pairs of the following heights: 1/2'', 5/8'', 3/4'', 7/8'', 1'', 1 1/8'', 1 1/4'', 1 3/8'', 1 1/2'' 1 5/8''.