What diameter extension hoses are compatible? The pressure hose connection is a M22 15mm. We have a 25 Ft extension pressure hose (SPX-25HD) that connects to the existing hose. Related articles Sun Joe High-Pressure Washer Hose Compatibility Guide Can I use another brand's accessory with my Sun Joe pressure washer? Can I use an aftermarket spray nozzle with the quick connect wand? Can an outdoor extension cord be used with this machine? Understanding Wear & Tear Parts on Your Shop Joe® Product