Retro Valve and X-Valve?

[NeilS300]

Is there any difference between the Retro Valve and the X-Valve besides the weight? Because I want to get the Ule trigger and it says it is best on the x-valve. Does that mean that I can use it on the retro valve and it will be the same?

[BlackHalo]

As long as your Retro has 2 O-rings at the bottom of the On-Off you can use the ULT.