Quickun 5/16" Hose Barb Fitting Plastic Equal Barb Joint Splicer Mender Adapter Union for Tubing Pipe Air Line (Pack of 5): Amazon.com: Industrial & Scientific
Anderson Metals 53701-0608 Pipe Fitting, Nylon Hose Barb, 3/8 ID x 1/2 In. MPT - Quantity 10 - Pipe Fittings - Amazon.com
Everbilt 5/8 in. Barb Nylon Tee Fitting 800399 - The Home Depot