It is wirelessly programmable via an Apple II with a modified version of BASIC called TopoBASIC (and later Forth with TopoFORTH).
It also cannot communicate back with the Apple II any information, nor calibrate its own motors to ensure an accurate task is being performed[14][15][16][17] The robots were sold commercially starting in May 1983, and were intended to be inexpensive, lacking a complicated manipulating device.
This last iteration removed the detachable arms, instead going for swappable trays, alongside consolidating the ABS plastic shell into just two pieces.
Topo IV's spec sheet was closer to Androbot's Brains On Board line of robots.
Units are beige molded plastic with two drive wheels as feet and stand 36½ inches tall.