Summary: Released during the 2009/2010 season, the Pieps Checker is a tiny device that you can use to test avalanche transceivers. It's primarily intended for backcountry guides so they can test their client's beacons before heading out in the morning (and maybe after lunch). It has a maximum range of 100 cm (1 meter).
Many newer transceivers now have a test mode similar to the Checker. A few can display the frequency and duration of the transceiver that is being tested.