I have an Attellus brand child's arm immobilizer for sale.
It has 3 Velcro cuffs: One for the upper arm, one for the forearm, and one for the hand.
The main support wraps around the waist with a stretch elastic allowing it to fit many different waist sizes.
Colour is black. I paid $30.00 at a hospital and it was used by my 11 year-old son for about a week. Condition is like new.
See my photos for more details, thanks.