I am selling the booster seat we got for Max as he gets travel sick and seems slightly better in his crate than this.
It's made by Solvit and is called the Tagalong Booster Seat and is size medium.
It comes in the original box and is in very good condition. (The lining is removable so has been washed a few times.)
Holds dogs up to 12lbs and measures 14" W x 12" D x 8" H.
All the details are on this link:
It cost me £35 and I'd be happy to sell for £20 including postage within the UK.
I have included a pic too so you can get an idea of what it looks like:
Just let me know if you're interested!