Surface marker buoy - Wikipedia

File:Bottom deployable surface marker bouy P9040104.jpg - Wikimedia Commons

Diving shot - Wikiwand

Null Island - Wikipedia

Buoy - Wikipedia

Buoy - Wikipedia

Surface Buoy SpringerLink

The latest version of the SubGravity SMBs, these new Gen 2 SMBs feature dual bungee retaining loops for maximum security when stowed.

Surface Marker Buoy (aka SMB or DSMB)

Diver Below Surface Marker Buoy--High Visibility Reflective Band on the double sided of the diver down flag, pointing out there is diver below . There

DSMB 4ft Surface Marker Buoy with 100ft Finger Spool Reel Diver Below Signal Flag Tube Scuba Diving Equipment Open Bottom Set (4ft)

Types of Surface Marker Buoys & How to Use Them - AquaViews