This holster is incredibly versatile. It attaches to your gear with two molle strips, so it will work with any molle loop gear or on a belt. You could also tuck the molle straps under the horizontal loop and slide a belt through to mount the holster horizontally. It also has a D-Ring you could use to clip to anything with a carabiner.
The fit for a Hurricane blaster is perfect and slides in and out with ease while feeling very secure.
For Dominator 40 Round Magazines the fit is slightly loose, allowing for easy access. The sides are made of straps instead of being a pouch, so returning a mag to the holder may be more difficult. The male side of the clip is removable if you feel it is in the way.
Fit for water bottles will depend on the size and shape of your bottle, but it holds my 2.5in diameter bottle like a dream.