Amazon.com: STYDDI Pressure Washer Quick Connect Kit for Sun Joe SPX Series, M22 15mm to 3/8 Inch Quick Hose Connect Fitting Coupler Compatible with Sunjoe, Campbell, MI-T-M, Stanley Pressure Washer, 4 Pieces :
American Pressure - Spare Quick Coupler Set, 1/4, 3/8,
Powercare 3/8 in. Male Quick-Connect x Female NPT Kit for Pressure Washer AP31037B - The Home Depot