【JOKERDRIVER】SPRING S 10mm 's Japan Review

I use it with a joker driver weight ball and it holds the ball in place when used with this one. I am glad I bought it, with the caveat that the proper length must be chosen depending on the number of balls and the depth of the groove.
If the spring is bent, there is a risk of not being able to remove it, so you should only be concerned about that.