Protecto Butyl BT20XL Window Flashing Tape 6"x75' Bt25-xl window and door flashing tape, self-adhesive, 25 mil thickness, 6 in Width, 75 ft length, HDPE, white, 975 psi tensile, 45 - 240 deg F, 1 27 specific gravity, ASTM e331-90, for window and door installations to create a positive air/vapor barrier in everyday construction For straight run applications