Thread fitting made of stainless steel (V4A) > Reducer AG(R) x IG(Rp) reduces >>> 1/8 to 4 inch desired size simply choose yourself > 1 1/2 inch to 1 inch. : Amazon.de: DIY & Tools
Amazon.com: WYNNsky Tank Mini Ball Valve, 1/4''NPT Female Threads×1/4''NPT Male Threads, Shut-Off Air Compressor Accessories Fittings : Industrial & Scientific
Parker 68P-8-4 Compression Fitting for Thermoplastic and Soft Metal Tubing, Poly-Tite, Tube to Pipe, Brass, Compression and Male Pipe Connector, 1/2" and 1/4": Amazon.com: Industrial & Scientific
RAINPAL BBF020 LF Compliant Brass Bulkhead Tank Fitting (Double Female 1/2” NPT and Male 3/4" NH Garden Hose Threaded, 4 oz each) (1) - - Amazon.com