Well, it works well on squonk mods WITH AN ADJUSTABLE 510 only.
Yeah, I stood on my caps key for emphasis. I have the BF and it won't make contact on any of my squonk mods with non-adjustable 510 connectors.
I tried it on three Coppervape mods and a Boxer clone and the 510 on the Serpent BF was too short to contact the 510 on the mods. On my Pulse BF mods and my Reos, it works because those mods are either spring-loaded or adjustable.
Having said that, my Serpent BF came with the tiny 510 plugs - though I have never tried using them - and the RDA is currently one of my favorites. I'm using it on one of my Pulse BF mods, with dual 26ga kanthal coils and getting great vapor and flavor.
Lastly, I was very disappointed with Wotofo's customer service. After blaming me for using it wrong, which I disproved, they bailed out by saying I didn't buy it from an authorized reseller (3fvape) so they "couldn't help" me. Sad.