Size:about 8mm in width,U choice diameter size
(please dont use your image to judge size,1-2 mm allowable error)
Size Reference
6 size=16mm in diameter
7 size=17mm in diameter
8 size=18mm in diameter
9 size=19mm in diameter
10 size=20mm in diameter
11 size=21mm in diameter
12 size=22mm in diameter
13 size=23mm in diameter