The Human-Signs (ヒューマンサイン?, lit. Human Sign), Human-Sign Blue Hyūmansain (ヒューマンサイン・ブルー?, lit. Human Sign Blue) and Human Sign-Red Hyūmansain Burū (ヒューマンサイン・レッドHyūmansain Reddo ?, lit. Human Sign Red) are transformation devices given to children to transform Junichiro and Junjiro Iwaki into Human No. 1 and No. 2. They first appeared in the 1972 tokusatsu kaiju show, Assault! Human.
The Human-Signs are disc shaped, and colored to match the hero they transform (Human-Sign Blue being blue to correspond with Human No. 1, and Human-Sign Red being red to correspond with Human No. 2). Each one has an image of a Human mask, and just above it, a small hole is visible. A rod would be put through that hole and spun during the show to transform the Humans.
At the beginning of the Assault! Human live show, Human-Sign Blues were passed out to the children in the crowd. If Junichiro Iwaki was in trouble during the show, the children would be cued to spin their Human-Sings, which would allow him to transform into Human No. 1. After episode 9, when the Human No. 2 character was introduced, Human-Sign Reds would be passed as well as the blues to transform both Humans.
- Children given the Human-Sings were allowed to take them home as souvenirs.