This is just the whip, they also sell it paired with their new Calyx inline HT, it's a modular system. I'm not as wild about the Calyx, it's body is too short for the minimum amount of water. https://www.xhl3.com/collections/glass-mouthpieces/products/nebula-whip-kit I use the whip with a @Ratchett 18mm SonG. I've also used the Nebula mouthpiece mounted directly into the MV (without the whip), but I'm usually running at red temp and it needs just a bit more cooling for me. It may work great at lower temps or for others.