Click to expand Tap to zoom John Guest 3/8 to 3/16, straight reduction by John Guest Sale 19,00 kr Only 4 available in stock - order soon. 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart With this adapter, connect a hose or tube 3/16 at one end and fit on another John Guest with opening 3/8. Our hoses are in stock and have dimensions that fit these couplings.