Package content:
6-7mm --------------------------- 20pcs
7-8.7mm ------------------------- 20pcs
8.8-10.5mm --------------------- 20pcs
10.3-12.8mm ------------------- 20pcs
12.8-15.3mm --------------------20pcs
15.3-18.5mm --------------------15pcs
17.8-21mm ---------------------- 15pcs