I made this T120 keychain with fluorescent beads. Compared with C60 keychain, I believe that T120 is even more suitable for this purpose. This is because T120 is flat, while C60 is round. When you put a C60 keychain in your pocket for a few days, the line that holds the ball tight can easily become loose and relaxed. The T120 keychain does not seem to have this problem.