Prim's short thumb passive orthosis. It is used for Quervain's tendonitis, which is inflammation of the tendons at the base of the thumb, due to repetitive movements. It has a double layer made of thermofoam with aeration system and radiotransparent. Its weight is almost negligible and 45% less. The outer layer is made with a high density foam that gives it exceptional rigidity. It is soft and very pleasant to the touch. The inner foam is a perfect cushion for the patient to feel comfortable. The splint is adapted to the contour of the hand by applying heat through an air gun. It is easy and comfortable to work with. It has two fastening buckles. It is available in grey and white.