As the title says, it's an airsoft claymore that is tripped by a laser (or lack of). Here's a video that will inevitably do a much better job at explaining than I could ever:


And the product itself:
http://redwolfairsoft.com/redwolf/airsoft/Special_Weapons_Supercell_Development_Supercell_ASC7_Claymore_Mine_with_Wired_Remote_and_Laser_Tripwire_Unit.htm

For those who didn't watch the video all the way through, the claymore actually looks like quite a pain to set up. It requires a separate laser to be set up and shining into the laser receptor (?). Since the receptor is slightly raised off the ground, you'll likely need to build some kind of adjustable mount to get the laser to aim just right at the receptor. Regardless of whether you have a mount like that or not, the entire process would be a pain in the field. You can forget about pulling out a claymore, stabbing it into the ground then sitting in a bunker like the camper you know you are. At least with this claymore.