Thermoplastic masks are made from low-temperature thermoplastic materials, primarily polycaprolactone (PCL), which softens at relatively low heat and conforms gently to the patient’s anatomy. These masks are compatible with various baseplates and are available in multiple configurations tailored for head, neck, shoulder, breast, pelvis, and limb immobilization. They come in two thickness options—2.4 mm and 3.2 mm—and two perforation types—22% and 36%—to suit patient comfort and clinical precision. Being low-temperature thermoplastics, they are easy to mold and reshape during simulation and treatment phases.