Although I am impressed with the design and build of this case back opener, I was disappointed to note that there was an error with the lug jigs that were included. They are supposed to come in matching pairs, (2) 20/22 mm; (2) 17/19 mm; (2) 15/13 mm; and (2) 11/9 mm. Mine did include the correct count of the 20/22 and 17/19 mm jigs, but there were (3) of the 15/13 mm jigs, and only (1) 11/9 mm jig. It is probably unlikely that I would be opening watch cases with lug widths of 11 or 9 mm, but it would have been nice to have a complete matched set.There are no instructions included, but it's not that difficult to figure out how to use it.