2 # size: outer diameter of big head: 21mm, outer diameter of small head: 17mm, height: 18mm
3 # size: outer diameter of big head: 23mm, outer diameter of small head: 18mm, height: 16mm
4 # size: outer diameter of big head: 27mm, outer diameter of small head: 22mm, height: 19mm
5 # size: outer diameter of big head: 22mm, outer diameter of small head: 18mm, height: 27mm
6 # size: outer diameter of big head: 28mm, outer diameter of small head: 22mm, height: 18mm
7 # size: outer diameter of big head: 38mm, outer diameter of small head: 28mm, height: 25mm
