5" Fret Saw with Lever Tension and Swivel Blade clamps. Designed to swing the rear of the frame out of the way. The ability to set the frame into a "neutral corner" frees you to saw into areas that were never possible before. It swivels45° degrees either to the Right or the Left, and has a lock at the “straight ahead” position. Truly the ultimate in saws. You can saw the base-line of dovetails without any frame interference. 

Please check out Christopher Schwarz's review here, a great source of info on this amazing saw,   http://www.popularwoodworking.com/woodworking-blogs/chris-schwarz-blog/knew-concepts-fretsaws-approach-perfection