A modified saxophone developed in 1999, available in both E flat contrabass and B flat or C subcontrabass sizes.

The E flat tubax has the same register and fingering as a regular contrabass saxophone (much like an E flat contrabass sarrusophone) but is much more compact due to its tubing being folded more times. It has a narrower bore (also like a sarrusophone) and is made to take a baritone saxophone mouthpiece. While its timbre is more focussed and compact than that of the full-sized contrabass saxophone - perhaps more like a contrabass sarrusophone with a single reed mouthpiece, it still blends well with other sizes of saxophones and can be played with surprising agility compared to its size.

The subcontrabass tubax uses a baritone saxophone or bass saxophone mouthpiece.

More recently, variants have been produced in CC and BBb, the latter pitched a full octave below the bass saxophone.

There is some debate over whether the tubax is really in the saxophone family. Its bore is not as wide and the tubing is very thin compared to other saxophones of equivalent size and its sound is a little bit 'honkier' than the average saxophone.