Thermo-Form Thumb Splints. Short Length, Right Thumb, X- Small. Made of a smooth, comfortable, durable neoprene-type material. Comes with a thermoplastic piece that can be easily molded directly on the patient using warm water (160-170 degrees F) for a custom fit. Features a pocket on the inside where the thermoplastic material is inserted. Thermoplastic insert is removable from pocket when cool.