[Hockey Puck Replacement] Which Urethane do I Use?

Hi All,

I've read several times that one source for replacement urethane in the suspension units is McMaster-Carr but I'm having a hard time pinning it down for some reason. Mine are old, old, old and need redoing. I would really appreciate it if somebody could tell me exactly which grade they would recommend. All I've found so far are these: http://ift.tt/2k1ponZ

Am I on the right track? Other suppliers? Better material suggestions?

Thanks very much!

[Hockey Puck Replacement] Which Urethane do I Use?