Quick question-- Why do some bats have a small "tm" stamped on the knob end and then some do not? I've been wondering this for a while now but really didn't worry about it too much until I just purchased a bat and noticed the "tm". Its a 73-75 model. I also know not all of my 73-75 models have it, or at least I dont think they do. Why is this?

Thanks for your time!


Middle bat.