This game was made in a 4-player version Williams' 1975 'Pat Hand' having a similar playfield and different artwork, except that game has three flippers instead of four. Nothing is known about the Engineering Prototype shown here except for the fact that it is labeled as such inside the game and the cable route under the playfield had been marked by tape. We were unable to learn if the cabinet has a serial number, often not the case with such games. The games pictured in this listing show two styles of pop bumper caps. Williams used either of these two styles in their games produced from May 1973 to January 1976. We expect that their flyer predicts the style that was used for the entire production run. Most likely, whenever the caps needed to be replaced, operators used whichever style they had handy, as either one would fit on the pop bumper bodies of the games Williams made during this period.