The Epitact Proprioceptive Orthosis was designed for people suffering from pain in the trapeziometacarpal joint of the thumb, often caused by rhizarthrosis or repetitive movements. Its action consists of limiting the traumatic micromovements responsible for the pain, keeping the thumb in a functional resting position without hindering normal hand use. The EPITHELIUMFLEX® technology, based on a silicone gel tendon, helps stabilize the joint, slightly increase the space between the thumb and index finger, and retain local heat, helping to reduce joint discomfort during movement. The orthosis allows you to perform tasks such as writing, driving, using a mobile phone, or working, while maintaining dexterity in the other fingers. Its ultra-thin, lightweight, and discreet design fits easily under clothing and allows you to wear watches or bracelets without discomfort. This orthosis is complementary to rigid orthoses for nighttime use and is especially suitable for daytime use. This version is designed for the left hand, in size S, recommended for a wrist circumference between 13 and 15 cm. It is machine washable at 40°C and is designed to maintain its effectiveness for several months of normal use.