I recently got an air kit from Stupid Simple Tools (really nice kit, some issues, not sure why it is no longer on their site or I'd link it...) I wanted to use type-V high-flow couplers everywhere since they get ~74 cfm vs ~40 cfm for type-M ("Industrial", the typical coupler here in 'murica).
I wanted to buy them from Milton directly to avoid Amazon counterfeits (which are hugely prevalent and dangerous in my other hobby: circus rigging). It. Has. Been. An. Uphill. Battle... to get any customer service on two orders that are now clocking in at 2 months old. Contact via email (three times!) for any order questions: no answer. Ok, use the site's web page for support: no answer. I call the support line. It is just an answering service that takes your issue so they can not deal with it and hide behind their red ribbons with white stars and occasional eagles to make you feel like you're supporting American industry. (Wait for it!) No answer. Just emailed that I'd do a Visa charge-back on both orders with all transactions documented. They hate this one trick that can get them pulled from Shop, their online cart service. (As an aside, Shop is a really nice cart integration and this from a former PayPal contractor... PayPal is just, well, can't explain here because it is completely stolen from xxx payment sites haha!)
So if you want the nice type-V, as you should, do yourself a favor: while looking for an adaptor at Harbor Freight, I noticed that they have complete Milton ColorFix clones under the brand Merlin. They. Are. Identical. Buy those. I'm getting those and absolutely will roast Milton when I restart the channel. I get it some people will think Milton has the IP for type-V so we should support them not the clone, but type-V are "euro-style high-flow" meaning this is a clone of what Europe has been using anyway.