Tefen Fiberglass Polypropylene Compression Tube Fitting, Tee Adapter, Blue, 6 mm Tube OD x 1/4" BSPT Male x 6 mm Tube OD (Pack of 5): Compression Bulkhead Fittings: Amazon.com: Industrial & Scientific
Loc-Line Tefen Female Pipe Reducer Fittings - 1/4" to 1/8" - 40655 - Pack of 4 662633406552 | eBay