Quite impossible to find —and in original box this 1940’s Pilling and Sons Rubber Dental Dam #3500 holder is a nice accent to a dental manikin. Each holder has a little clamp system to hold the rubber dam in place. The elastic strap is rather old but has a little bit of elasticity to it or just enough to put around your phantom or human head. This would look best with the older heads that have shroud pins on the buccal plates and teeth sets. but as you can see I added it to a more modern MQDM head.