Specifications: Material: Metal + Plastic Size of the dies: Round shape use both size: 18-20 mm, 21-23 mm, 24-26 mm, 28-30 mm, 31-32 mm, 33-34 mm, 36-38 mm, 40-42 mm, 43-45 mm, 48-50 mm Rectangular shape dies size: 20mm, 25mm, 30 mm, 35 mm, 40 mm, 45 mm Round shape dies use only 1 side: 10mm, 16mm 2 dies on different shapes: 37mm, 45mm Features: Dies with different sizes can meet your different demands. Specially designed for watch repair,which is professional and full set design. Made of high quality metal and plastic, tough material, super durable,long service life. Plastic dies with a metal screw in the middle make it more durable, and won't scratch your watch. Package Included: 1 x 20Pcs Watch Back Press Fitting Dies