4 Universal 5 Prong Clock Keys Wind All Clocks Tool. Two 5 Sided Clock Keys. This is a new set of two 5 sided clock keys. The sizes are: Size 2, 2.75 mm. Size 3, 3.00 mm. Size 4, 3.25 mm. Size 5, 3.50 mm. Size 6, 3.75 mm. Size 7, 4.00 mm. Size 8, 4.25 mm. Size 9, 4.50 mm. Size 10, 4.75 mm. Size 11, 5.00 mm 2 New 5 In 1 Pocket Watch Winding Keys. This is a new set of 2 five sided pocket watch keys. These can be used with a variety of pocket watches. The sizes are: Size 2, 1.75 mm. Size 3, 1.65 mm. Size 4, 1.60 mm. Size 5, 1.50 mm. Size 6, 1.40 mm. Size 7, 1.30 mm. Size 8, 1.20 mm. Size 9, 1.15 mm. Size 10, 1.05 mm. Size 11, 1.00 mm.