According to certain embodiments of the invention, a pressure washing system delivers a cleaning fluid under pressure to a surface to be cleaned, and includes a fluid pump unit for supplying the fluid to the surface. A first conductive path is electrically coupled to the at least one line terminal. The locking ring has an uncompressed diameter selected to exert lateral force on the groove in the box end when assembled to the pin end. When the torque equal to or greater than a predetermined value is transferred, a slip is generated in a rotational direction between the rigid cam plate and the hub, thus limiting the transfer torque to a predetermined limit value. Pixels of subsequent images are also mapped into corresponding color space regions while incrementing counts in records of those color space regions. A latching portion extends radially from the post and adjoins the operating portion.