An assembly of non-sterile devices designed to produce a thermoformable splint intended to be applied around the upper limb of a patient who requires support or immobilization (e.g., to treat fractures, injuries, sprains). It typically consists of a low-temperature thermoplastic material and a textile (e.g., cotton) in the form of the limb and into which the thermoplastic is inserted; the combination is warmed in a water bath for adaptability to the shape of the patient’s arm. It is available in various dimensions and may be used in various clinical specialties. This is a single-patient device that may be reapplied over a short term (single-use) before being discarded.