Polyester filament is suitable for use in strip brushes in some environments and applications where neither polypropylene nor nylon make a good fit. Polyester is less stiff than polypropylene and comparable to nylon in dry stiffness modulus, but superior to nylon in wet stiffness due to its lower water absorption rate. Like nylon, polyester offers a higher softening and melting point than polypropylene, and superior memory or bend-recovery. Polyester excels over nylons and polypropylene in high-temperature oxidation resistance, or the tendency to lose physical properties over time at elevated temperatures. Polyester is less expensive than nylons, but slightly more expensive than polypropylene filaments. Polyester is available by special order in FDA-approved for food contact versions.