What is the history behind the 75th Ranger Regiment's...?

I'm buying my friend and aspirin Army Ranger s knife before he goes off to West Point this summer and I figured that I'd get him one that has the Ranger patch on it (I know that he couldn't carry it around at WP or until he does become a Ranger but I think it'll be a nice gift). Anyway, I keep seeing this USARA Dagger that's being sold as a great Ranger knife. This seems odd to me and I figured that It may have some historical background like maybe it's a traditional or ceremonial thing. Anyway, I just wanted to see if anyone knew. Also, if anyone knows a good brand of fixed blade knivesthat could have the Ranger logo etched into them? Thanks.