Compact laser line generator complete with belt-mountable pouch.
Unfortunately the manual levelling vials don't appear to be very accurate, so although you may get a straight line, it probably isn't plumb. (turn each vial through 180degrees and they give a different reading, so check your line with a reliable spirit level if you need accuracy.)
The magnetic wall mount system is a bit dubious, one is based on a tack which is driven into the surface you are marking, which holds the base to which the level is magnetically held to. It's somewhat of a loose fit, thus questioning overall accuracy. The other base requires a 4-8mm diameter hole into which a set of three splayed pins engage. This base is a better fit. Both will mark the wall though if the intention is to use it for lining up pictures etc. The holding magnet is a little on the weak side and the device can detatch itself a bit too easily if being used on a wall, which is not what you really want to happen when working with laser light.