For now, I use Divine Tribe Hydratube via adapters. It works great, but I still want poseidon for a shorter, less hydrated vapor path. The hydratube can strip terps, IMO. For those that use low terp stuff, I feel this is necessary to take some harshness out and make it bong-like. My late rips are a joy when the terps are gone.

I think for the poseidon it will be either a custom from u/Dabbercrombie, or a 810 mouthpiece that somehow has 15mm o ring channels similar to what the Molecule adapter has. I am looking right now.

I took some measurements which I am sure are available elsewhere, but mine came back with o rings of OD 17mm, ID 14mm. Thickness 2mm.

Please check my math before buying anything. I am using a cheap plastic caliper, but it seems ok.