Butyl Rubber (IIR — Isobutylene Isoprene Rubber) is uniquely characterized by its extremely low gas permeability — making it virtually impermeable to air and other gases. It offers excellent resistance to heat, ozone, weathering, dilute acids, and alkalis, along with good damping properties for vibration isolation. Essential for tyre inner tubes, pharmaceutical stoppers, gas masks, and architectural membranes.