How long a probe do you need? A bit longer than the depth at which your victim is buried at. To play it safe, especially in areas with a deep and active snowpack, try the Ortovox 320 pfa Avalanche Probe, an all-aluminum that's a good 20 centimeters longer than many other companies' longest. Ortovox's Patented Flash Assembly (pfa) System assembles and disassembles in, you guessed it, a flash.