Yeah, the tail-fin and the saddle. That's what I was looking at materials for. I don't have a replacement for his fin with me, so if this one got damaged when we're out past the fences, I'd have to fix it... somehow. He can't fly without it. [He's pretty proud of the design, the thin metal rods and pins and cording that attach the foldable tail fin to his tail, and in turn is hooked into the saddle, which has a pedal mechanism that his prosthetic foot slips into perfectly. It's a very purposeful design, a little rustic in the materials department, but well thought out.]