"These pouches are great for the flashbang sized nades, but not exactly required. Those shape/sized nades will fit into M4/M16 double mag pouches. The difference is that the actual pouch is cut off shorter on these, while the velcro strap goes over more of the nade. In other words, the nade will fit half about 2/3rds into the pouch, with the velcro over the top, leaving 1/3 exposed. It's easy to pull it out. Where as a M4/m16 mag pouch will have the nade completely covered, proving slightly more difficult to pull the nade out. Really wish they'd make some nade pouches with buckles instead of velcro, like they do for frag nades (far too small of pouches to fit thunder b, or tornado sized nades. Typically nades will be used for clearing a room, or putting it in someone pocket then running away. In other words, generally for stealthy assaults. You toss it into a room hoping it'll go off before the victims notice, or that by the time they notice, it's far too loose. the loud ripping sound makes them look in your direction, then they see you tossing it, and have a good chance of retrieving it and tossing it back. Sure if the guys are firing their AEG's, they probably won't hear the sound of velcro over the noise of their motor just inches from their ear, but between shots, they can hear it.
One thing i do appreciate that most overlook, is the loop on the velcro straps. With a nade, firing pins are easy to lose, especially in forested areas. So what i do is tie some fly fishing line to the ring, with about 12 inches of slack, then tie the other end to the loop on the velcro. This makes it so that when i pull the nade out of the pouch, i have 12 inches to get a comfortable fit over the lever (think it's called spoon, whatever the lever holding the firing pin is called) and then when i raise it up to throw, the pin is auto pulled, but not lost. Putting a pin in a dump pouch is a good way to loose it, because it's such a small object in such a big bag. same with putting it in a pocket, or the pouch itself. Some sort of string/cord attached to it is the only sure fire way of not loosing the pin. That or get a magnetic strip (a strong enough one to most likely not lose the pins.)