Good ideas can be so amazingly simple: like Seareq's DIVETY!
DIVETY is a SOLAS * reflector that is tailored to fit the corrugated tubes of diving and buoyancy compensating jackets / vests. The back is fully equipped with Velcro. This means that the DIVETY can be attached to any corrugated hose or other points of the diving equipment in no time and can also be individually fixed to smaller diameters.
That makes even the Darkest jacket glow.
The effort is minimal - the effect is all the greater:
Fixed at the highest point (e.g. at the upper end of the corrugated tube in the shoulder area), the DIVETY can save lives in an emergency if it reflects the light from searchlights or sunlight and thus draws attention to the diver.
*SOLAS stands for "Safety Of Life At Sea" and is an international valid certification of IMO, International Maritime Organization for seafarer equipment. It is a division of the United Nations Organization UNO to regulate all affairs of the sea. The SOLAS certification of the reflectors guarantees a durable quality of the material. It does not get blind, green or yellow regardless of the number of use in salt or fresh water.