So while not the first coin-op commercially produced video game (Computer Space), Pong was Atari's first game and also was the first video game we know of for which a conversion kit was sold (by a third party). Not to be confused with the countless pong knockoffs that soon followed, JRW's Handicap was intended to upgrade/convert an existing Atari Pong cabinet. In the one in our collection, it actually consists of a daughter board that connects to and retains the original Pong pcb (along with an upgraded control panel)! Each player can independently set their own difficulty level (paddle size) and manually serve the balls...
I thought I'd share since the JRW version isn't well known (even amongst the coin-op oriented KLOV members on my site) but its place in history as the first coin-op video game conversion and connection to Atari's first game seemed to warrant sharing here.
Side note: This isn't the first arcade conversion. Arcade machine conversions have been popular since at least as far back as the late 1920s (1926 to 1929), and were quite common during World War II as new games weren't been made while factories were focused on supporting the war effort.
2 photos of control panels from machines in our collection: The first is from Pong serial #1 (ex-Curt Vendel, signed by Nolan Bushnell). The second is from our JRW conversion machine.