Amazon has the Thames & Kosmos Geckobot Wall Climbing Robot for $21.59 was $49.95!
Geckobot model walks vertically up smooth surfaces like windows, glass, and mirrors.
Learn about the physics of air-pressure, suction, and surface texture.
Build 6 robotic models, in addition to the Geckobot; 7 different models in all.
Ages 8+, 24-page, full-color manual and experiment guide with step-by-step instructions.
A step-by-step construction and troubleshooting video walks you through the building process for the Geckobot model, and is viewable here: https://vimeopro.com/thamesandkosmos/productvideos/video/178953549.