Material: durable stainless steel.
180 Pieces watch band spring bars in 18 different sizes includes 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm.
Those watch link pins are kept in a transparent plastic box for keeping the 18 different sizes separated and easy to access.
Diameter: 1.5mm/ 1.8mm
Since the size above is measured by hand, the size of the actual item you received could be slightly different from the size above.
Item color displayed in photos may be showing slightly different on your computer monitor since monitors are not calibrated same.