24 New Bergeon Pocket Watch Winding Keys. This is a new set of 24 pocket watch keys. These are used to wind pocket watch mainsprings. There are 12 sizes with 2 keys for each size. You receive: Two size 1 pocket watch keys each with a 1.80 mm hole. Two size 2 pocket watch keys each with a 1.75 mm hole. Two size 3 pocket watch keys each with a 1.65 mm hole. Two size 4 pocket watch keys each with a 1.60 mm hole. Two size 5 pocket watch keys each with a 1.50 mm hole. Two size 6 pocket watch keys each with a 1.40 mm hole. Two size 7 pocket watch keys each with a 1.30 mm hole. Two size 8 pocket watch keys each with a 1.20 mm hole. Two size 9 pocket watch keys each with a 1.15 mm hole. Two size 10 pocket watch keys each with a1.05 mm hole. Two size 11 pocket watch keys each with a 1 mm hole. Two size 12 pocket watch keys each with a.95 mm hole.