Our premium gas hose is perfect for both indoor and outdoor usage. The non-whistle gas flex line will remove the annoying whistle sound often heard from a gas appliance, fire pit, or gas logs. Sometimes the whistle is so loud you don't even want to turn your gas on. Many things can cause the whistle, but the bottom line is that our non-whistle flex line is designed to remove it. Now, there could be too much pressure every once in a while, and nothing will eliminate the whistle. It's not a faulty line; it's excessive pressure. In that case, it's good to know you have a different problem. Turn off the gas at the source and call a licensed professional. Our flex lines will make any installation easier whether or not you have a whistle. So why take a chance? Place your order for non-whistle flex now to avoid the dreaded whistle. Flex Line Sizing: Flex line size is referred to by the fittings it uses and NOT by the ID of the line. For example: a flex line that uses 1/2" fittings will be referred to as a 1/2" flex line even though the OD is 1/2" and the ID is 3/8". Choose the shortest line possible for your project. The length of the line will affect BTU output. Note: We strongly recommend that all gas products be installed and serviced by professionals that have been certified by the NFI or WETT.