Crank bros Joplin 3 seatpost, 31.6 dia.
Good condition, mechanically, but needs new internal O-rings to work reliably. Shaft bushings replaced about 6 rides ago.
It's a pretty easy job to do (about as difficult as servicing a pair of RS forks), but as the post is surplus to requirements, I can't be arsed to do it, just so I can add £15 or £20 onto the for sale price. Perfect for the mechanically savvy dropperpost-curious.