Raide Soft Flasks are made by Hydrapak & thoughtfully designed in collaboration with Raide for each use case in their offerings. They all use a HydraPak low profile locking cap that keeps the nozzle from leaking under the pressure.
Specs
360mL : Soda Can volume for use in Raide Shorts & Belts (the moderate volume also works well in other less structured belts)
500mL : For short to medium runs, stacks on top of the 650mL soft flask in the back of the LF 2L Belt (fits filter tops)
600mL : For medium to long runs, with a tapered bottom it's designed to work with the LF 5L Vest (fits filter tops)
650mL : For medium to long runs, for use as the main hydration source in the LF 2L Belt (fits filter tops)