Watch band link cotter pins in 18 different sizes, and each size includes 20 pieces: 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm.
Stainless Steel watch pins spring bars with double shoulders, used for metal watch strap links.
Those watch link pins are kept in a transparent plastic box for keeping the 18 different sizes separated and easy to access.