The Poseidon Bubbler for the Sai Plus is the same as the V2 Poseidon Bubbler for the original Saionara, but it was built fo accomodate the larger 25mm diameter.  The mouthpiece is removable to make filling and cleaning much easier.  This version does fit the Sequoia atomizer since it is just a rebranded Sai Plus.  

In The Box
1 Poseidon Bubbler for Sai Plus