Polyesters are typically crystalline thermoplastics with excellent chemical resistance, relatively low water absorption, and excellent tensile and electrical properties. They are applicable in dental instruments, IV components, medical textiles, and films and packaging. Copolyesters are produced when more than one diacid is used in the polymerization process. These polymers are amorphous, have good impact strength, and are easily processable. Copolyesters are applicable in the use of IV systems, vials, and medical trays.