I've watched them from up close; that "device" is simply an Android smartphone. If you've parked over time (in 75 or 90 minute zones, they'll take a picture of their chalk mark too.)

The ones I don't like are the robot "meter maid" cars studded with license plate readers and cameras - no need form them to mark each car, it just alerts when they're passing one that was there during their last lap. Easier for them maybe, but as a parker I prefer the chalk so I can tell whether they've come by yet or not.

p.s. I'm in SB too - let's grab a coffee.