My sleeve board is one of my favorite sewing tools. I use it almost daily and love it so much I bought a second one when my original was packed away in a box during a move and I couldn't find it. It is a very small and narrow ironing board and each side is a different width.
It is perfect for pressing seams flat when making things like the Box Wallet, Curvy Clutch, Pixie Handbag or City Tote.