is there a difference between "X" valve and "x-valve"

["t-mac"]

I have seen valves that have just the X, and then I have seen valves that have the letters "X-valve" on it. is there a difference between the performance of these two valves. is one better than the other. any help would be great.

thanks,
tim

[CaliMagFan]

same same. aluminum RT valves are both.

[michbich]

As far as i know, they are identical.

[surfbum]

the only difference is the "x-valve" is an earlier run, but the exact same thing

["t-mac"]

thanks guys