These Life Floats come in two versions. The standard T models have a tough, resilient vinyl surface with reflective tape. They are easily boarded, comfortable in the water, and have no hard surfaces. GRST models have a thin fiberglass reinforced skin (with reflective tape) over the vinyl surface. This produces an almost impenetrable covering, yet remains slightly resilient. Light weight makes these very easy to handle, yet easily exceeds the most severe USCG tests No exposed metal hardware - all metal hardware is secured inside the float body Double webbing; sunlight and weather never reach internal supporting beckets Solid closed-cell plastic throughout; even bullet holes would have only a minimal effect on buoyancy Will not rot or mildew