If you are looking to replace with the identical pump you need to observe the position of the hole in the arm

3600 PSI Maximum Rated Pressure

Synthetic String Wound Elements

5 gpm water flow

Use for Interpump Series: E3

Interpump "66 HT Series" HT6646 High Temperature Pump 2900psi 12.15gpm Solid Shaft features_front-load-spray-gun If you are looking toInterpump 66 HT Series HT 6646 high temperature triplex pressure wash pump. 2900 PSI Maximum Rated Pressure HT Series can pump up to 185F HOT WATER 12. 15 GPM @ 1750 RPM 10. 04 GPM @ 1450 RPM Shaft Diameter: 24mm Inlet: 3 4" FPT Outlet: 3 8" FPT Unloader sold separately. Do not install pump without unloader or pressure regulator. Professional installation is recommended.