A RECCO reflector is a small, passive rescue device built into the jacket that helps search and rescue teams locate you if you're buried in an avalanche. It reflects a signal back to RECCO detectors carried by ski patrol and rescue teams—no batteries, no charging, and no activation needed on your end.
It's especially worth having if you ever venture off-piste, into the sidecountry, or anywhere outside groomed trails. It adds an extra safety margin that's always with you, and it's increasingly common on mid-range and premium jackets.
The critical thing to understand is that a RECCO reflector does NOT replace an avalanche beacon (transceiver). A beacon is an active device that lets your riding partners search for you immediately—RECCO requires professional rescue teams with specialized detectors to find you. Always carry a beacon and get proper avalanche training for any backcountry riding.