The most essential avalanche safety accessories are a transceiver and a shovel, the next most important item is a probe. These are extendible metal sections which form a rigid probe, necessary for exact pin pointing of victims. These will save time in the final part of the search process and are also used when the victim is not equipped with a transceiver or to determine snow pack depth.
Yes. A probe will pinpoint the exact location and depth of the victim and possibly alert the victim that help is at hand. If you are really unlucky then you can dig past someone, missing them by inches. Probes speed up the final part of the saerch process.
Typically 2 to 3 metres, some have coloured sections for easier measurement. The longer the better.
Usually between 100g and 300g.