I can confirm that the M3 works on these two from FT as I just got these in last week
$6.80 Derringer V3 Styled RDA Rebuildable Dripping Atomizer - 304 stainless steel / 22mm diameter at FastTech - Worldwide Free Shipping
$6.76 Derringer V3 Styled RDA Rebuildable Dripping Atomizer - 304 stainless steel / 22mm diameter at FastTech - Worldwide Free Shipping
Another Derringer V3 that I bought off of a friend a few months ago uses the M3. Not sure what the SKU is on it but it's a SS one
The first Derringer V3 I bought in April uses the M2.5. I pulled this from my FT history so it should be the same one.
$6.61 Derringer V3 Styled RDA Rebuildable Dripping Atomizer - 304 stainless steel + POM / 22mm diameter at FastTech - Worldwide Free Shipping
The 5th one I converted using a Hastur clone base that has the BF pin and I bought the Derringer ring and cap to fit it.
Buying both sizes of BF pins from FDV came in handy I guess.
I just ordered the v3 from ft with the intention of drilling it out my self. i couldnt trouble you for a pic of the deck with the squonk pin in could i?