Acetylene/Fuel Gas Adapter - A Size Female to 1/4 NPT Male Acetylene/Fuel Gas Adapter "A"Female-1/4"Male | Arc-Zone.com [WES-126] - $11.96 : Arc-Zone.com, Welding Accessories Store
3/8"MFL Adapter (Gas & Liquid) – House of Homebrew
2pcs Propane Adapter 3/8" Male Flare X 1/4" Male Npt Thread Coupling Fittings For Bbq, Coupler Pipe Flare Connector Gas Adapter - Fireplace Parts - AliExpress
Pneumatic Plumbing Brass Pipe Fitting Male/Female Thread 1/8" 1/4" 3/8" 1/2" BSP Tee Type Copper Fittings Water Oil Gas Adapter|Pipe Fittings| - AliExpress
BrassCraft 1/2-in x 3/8-in Threaded Adapter Fitting at Lowes.com
Amazon.com: Brass Hose Barb Reducer, 1/4" to 3/8" Barb Hose ID, Reducing Barb Brabed Fittings Splicer Mender Union Air Gas Water Fuel Line Heater Garden Pond Poly Tubing Adapter (Pack of 2) :
LASCO 17-6785 3/8-Inch Female Flare by 1/4-Inch Male Pipe Thread Brass Adapter - Walmart.com
Female Pipe Reducer 3/8" to 1/4" Npt Adapter Coupler Brass Fitting Water Oil Gas | eBay
BrassCraft 3/8-in x 1/4-in Threaded Flare x Mip Adapter Fitting in the Brass Fittings department at Lowes.com