Dreffco 3/4" x 30" Black Non-Whistle Gas Flex Line NG LP Fire Pits For Use Indoors or Out 3/4" Female Flared Fitting Each End. We've Included 3/4" Male and Female NPT Fittings For Your Convenience 30" 3/4" Non-Whisle Flex line is 5/8" OD and 1/2" ID x 27-5/8" Long w/o Fittings There Is a Staggered Pitch Every 2" to Eliminate Whistling Typicall Use Is for NG or LP Fire Features &gt;200K BTU with a 3/4" Connection Hub