Polypropylene strapping is the most commonly used and least expensive of all strapping materials. It's light and easy to apply and recycle. Characteristics include high elongation and elongation recovery, but low retained tension. Polypropylene is an excellent choice for light duty palletizing, unitizing, carton closing, and bundling. While it may be possible to use machine-grade strapping for manual applications in a pinch, hand-grade strapping should not be used in automated machines.