From the Bridge City Tool Works website - Layout your joints (or cuts) traditionally with a marking knife, awl or a pencil. Insert the appropriate guide block in the JM-1 JointMaker body and tighten. Now position the JM-1 JointMaker on your stock and tighten. Saw away, it's that simple! The JM-1 JointMaker guides your saw exactly where you want without slop or wobble. Your sawing rhythm becomes so relaxing and accurate you won't believe the results. All you control is depth of cut, which means you need to pay a little attention and the JM-1 JointMaker does the rest!

This is from the Signature Series line from 1999. Comes with original box and instruction booklet. Guide blocks are not included and I can’t find the original certificate of authenticity.