Not exactly an item that goes onto/in your PTW, but is a new "tool" in helping to load mags with. Just got mine in this afternoon. This will be a quick review at the moment (so more to come later on).
Initial impressions are this is seems rather well built, and like they say, it is 'big" in that it will definitely fit into a double M4 mag pouch. Has a bit of weight to it, but not in a bad way; so definitely not flimsy feeling like a normal speed reloader. You also no longer need to refill your loader b/t mags (unless using a hicap speedloader), as this thing hold 1,600 rounds
PTW mags do fit, but id wager are tighter then normal AEG mags would be. That said, all the type of mags i have here fit and accepted bb's. Mag brands i tried were: Magpul PTS ptw pmag, AirsoftGi "Bgrade" pmag, Tack pmag, Systema LE Pmag, Systema Pmag (that got w/ my NA PTW).
The small "negatives" I find at the moment (but could be since brand new) are, if you look at recent videos of it on youtube (one i saw from from about a month ago), it cranks VERY fast and loads quickly. It doesnt seem to crank and load as fast; but that could be b/c we/I am using it on PTW mags, and they were loading normal AEG mags. The other negative, is like all speed loaders (or ones ive had), you always seems to be stuck with having one last bb "stuck in the chamber".
That said, even though it is a bit pricey at $50 , i would recommend it, as no longer need to worry about having adapters (or losing them), nor having to fill a speed loader after each mag to fill up. Filling a mag takes around 10-15 seconds, and can prob do your entire mag loadout in roughly a minute or two; and then refill your Sidewinder to keep you going for rest of day for reloads reducing time needed back in starting area to refill mags/speed-loaders.
Initial thoughts and slight use, id give it an 8/10 ; but will update more as I use it.