Polyethylene Terephthalate is a strong, lightweight, transparent polyester plastic commonly used for beverage bottles, food containers, and clothing fibers, known for being safe, shatterproof, and highly recyclable (Recycle Code #1). It's valued for its barrier properties (keeping gases/moisture in/out), strength, and versatility, but it's not biodegradable and derived from crude oil, so proper recycling is crucial.