The Green Call is circular and its outer "shell" is a silver color. The inside/front of it is red with a black dot in the center. There are 6 circular lights placed on it which light up during the process of calling Greenman. This process is activated by pressing a small lever on the outside of the device.
The Green Call was first seen in episode 1 of Go! Greenman, Greenman vs. Garameddon. In the series it was used to signal Greenman. It also has the ability to repair Greenman's machinery, as shown when Cretin accidentally stepped on one of the Green Calls, and repaired Greenman of his paralysis in time for him to defeat Iho Killer. The Green Calls were also used to clear Greenman's mind control from Zarizon, and to cure the blindness incurred by Alien Tiborus.
One of the Green Calls also made a appearance in the crossover film, Go! Godman. Mika Ayase and Koichi Matsushita find the Green Call in a box of old toys and parts which was accidentally knocked over by Jilarji. Mika knew how to use it, (hinting she was in the group of kids given the original Green Calls) and calls Greenman to Earth so that he could aid Godman in battle against Jilarji and Gaira.
- The Green Call makes an appearance in the Go! Greenman opening
- The Green Call has made an appearance in every episode of Go! Greenman.