DIMS: approx 3.125" W x 4.25" H x 1.25" D (not counting PALS fins)
I've been quite the fan of the GEN II and based on user feedback and requests GEN III has recently come about. Down East Inc is still the main design crew while ITW distributes and markets the FASTmag. I'd say the largest change is that GEN III is now stackable and to assist in this, 2 versions are offered with one having PALS stabilizer pads and one without. The one with stabilizers is intended to be the main platform while the version without is for stacking or wearing on a belt.
On that note, a belt adapter is included with the non PALS stabilizer variant. I feel the adjuster could keep placement better, however it interfaces with ridges built into the new back straps to aid in preventing movement. The back straps have totally changed being made of heavy duty flexible material that lock into slots on the bottom of the pouch. Raised edges at the connection points prevent release giving this system a great balance of security while being able to detach without tools. The straps are nice and slim which is necessary to fit in the stacking slots on the FASTmags. They are also easy to mount on PALS webbing and despite that no weaving occurs, the stabilizer pads create a nice tight fit. In the unlikely event that the back straps become damaged beyond function, they can easily slip out giving repair capability.
I'd say a definite con is that on the interior only one side has 1 friction pad making GEN III less gripy than GEN II so I cannot recommend it for upside down use. Yea I know, I'm sure everyone was waiting for the next grip test dance video, but it just doesn't apply to GEN III. I'll guess the demand for stacking was greater than those who wanted upside down usage was the cause of this design decision. I reckon the 2nd friction pad was then dropped to keep depth size of the pouch minimal. Keeping with the right side up optimizations, there is no longer an included jump strap to keep costs down. Luckily there are slots in the back to allow users to knot up some simple jump straps with shockcord if desired bad enough. Only 2 slots are incorporated for the tension silicone bracelets rather than 3 as seen on GEN II. A third could be used up high, however it is clear in the design it was not originally intended.
It is clear the straps system is made to work just with the stacking system, but as a bonus MALICE clips can fit through the slots. Although gear will hang a bit low, you can get away with adding small accessory or pistol mag pouches. I'm personally sad to see reliable up-side-down capability go, however the integrated stacking makes for very easy mag grabs as the spacing between mags leaves room for beefy grips. The end result depth of 2 stacked FASTmags in GEN III is similar to a traditional triple NATO magazine pouch so most will find this to be an acceptable standard. As always, FASTmags aren't meant to replace all pouches, but any user can appreciate their speed and ease by not having to dick around with any flaps, straps, or cords to use reliably. Reinsertion is also easy which not many pouches can claim.