A diver-down flag warns boat operators that a scuba diver is in the water and they should proceed slowly, keeping a wide berth from the divers. The onus is on the divers to stay within a specific distance of the flag when near the surface, and also underwater. It is within a larger area around the flag that boats may not enter, usually between 50 to 300 feet of the dive flag. This flag is also used to identify a location where diving gear is sold or rented.