The Kodak STEP Slim ($100, marked down to $80 at press time) is a little printer with a single mission: To make 2 x 3-inch photo prints on the go.
Rather than transfer ink or toner to the paper, the STEP Slim uses Zink (as in, zero ink) technology. The thermal paper contains multiple layers containing dye crystals that respond to heat. There is a layer for each of the three colors (yellow, magenta and cyan), with each layer responding to different temperatures and heat pulses.
The battery is rated to last 25 prints or one-and-a-half hours. Charge time is also one-and-a-half hours. A micro USB cable is included for charging. Sending photos to the printer is done wirelessly via Bluetooth.