Once you've selected a unit, there's a hefty list of possible add-ons, including barcode scanners, smart card readers, Gobi-running 3G, LTE and GPS options.

ENGADGET

Computer Associates, a business software solutions company, have supplied all the technical equipment necessary to the forces taking part including computers and scanners.

BBC: missing posters

The TSA has defended the scanners, promoting their built-in privacy protection measures including blurring of faces and making it impossible for the machines to store or send the images.

FORBES: An EPIC discovery: Full body scanner images not as private as TSA claimed