FlashCo FlashCap vent pipe flashing.  Standard sizes for FlashCo FlashCap are 1 ½”, 2”, 3”, and 4”. Sizes referenced here are for standard plumbing vent pipe only. FlashCo’s unique design eliminates the need for a hose clamp in order to counter flash and instead uses a cap that just fits inside of the vent pipe and over the boot. See Drawings and PDS for diameter ranges and more information. The FlashCap is only intended for plumbing vent application and currently only available with a white cap. Our white cap can be painted by other to match other membrane colors.