Suflex Silverflex is custom-braided designed specifically for applications where temperatures as high as 1200 °F are encountered. For low-voltage applications, especially those involving heat, Suflex Silverflex fiberglass sleeving provides a sturdy, long-lasting and inexpensive insulation. - Suflex Silverflex is a braided fiberglass sleeving which has been heat treated (natural) or heat treated and impregnated (T and D for treated and dyed) with an acrylic binder.