GPS jammer plugs into cigarette lighter

Gpsjammer 02 640X

My favorite cheap spy-tech/weird cheap gadget seller, Brando, just announced a GPS jammer that plugs into a cigarette lighter. The description is sparse, but I am guessing it can be used to block navigation/tracking/logging systems that rental cars and company fleet vehicles sometimes use to keep track of drivers. It's $49 and I don't know if they are legal or not.

Gobal Positioning System (GPS) Jammer