pro-lite aerobuster seatpost alternative?

[Tommy2]

Got a frame that says to use pro-lite aerobuster seat post but was wondering if there was an alternative.

I'm assuming it's because of the aero shape all the way into the frame rather than standard size tube with aero upper.

I still want to use an earopost but would like a bit more choice if possible, so wondering if all aero post shapes are the same.

Cheers
Tom