Fingerprint sensors are cool things, but they’re also relatively bulky. Seiko Epson is aiming to change that. Researchers at the company are working on a super-thin sensor that measures in at just 0.2mm. Now that’s thin!

Like other sensors, it takes the measure of your current coming out of your finger and masks it to its memory banks: If it’s a fit, you’re in; if not, the sensor deactivates whatever device it is attached to. That’s not much of a second chance, although you have to figure that the fingerprint is either yours or it isn’t, and if it isn’t, you don’t want the device to become active.

This is probably a convenience that you’ll be willing to look into by the time these wafer-thin sensors are on the market, which the company says is in another four years.