Divers should always carry a signal devise when they dive. A Signal Mirror is a simple devise that allows a diver to signal long distances during the daytime when the sun is shining. XS Scuba's Rescue Flash Signal Mirror is a 3" x 2" (7.6 x 5.1 cm) Rescue Flash Signal Mirror with Aiming Hole for correct positioning. Mirror is handy to signal a boat, aircraft, people on land, etc. Mirror is manufactured from Non-Corrosive Material and has an Eyelet Hole on one corner for attachment of a line or lanyard.