This is a one of a kind hand-saw with a forged frame and a patent cam lock system for quick replacement of the blade. The saw frame is marked "PROPERTY OF TILDEN SAW CO. 2783". There is also a patent date on the cam level "PAT. 7.26.04". The patent marked is clear marked and the TILDEN MARKED is a bit harder to see. Overall the saw is in good working order with some grain split in the handle, but the handle is very solid and well attached (note how the handle is attached with screws on one side only, rare). The saw blade could use a sharpening, and there is some pitting on the saw frame, but this is a rarely seen cam lock system. I've not seen another.