Polyethylene buoy to the ship in distress, the release of smoke distress signals, in order to obtain help. In line with 1974 the International Convention for the Safety of Life at Sea 1996 (SOLAS 74/96) Amendment international lifesaving equipment rules of the International Maritime Organization (IMO), life saving appliances (LSA) test MSC resolution MSC.81 (70) 
 5555-2.5 buoy 
 1, the outer diameter of 710mm inner diameter of 440mm 
 2, in the fresh water bearing not less than 14.5kg of iron 24h years 
 3, with the quality of not less than 2.5kg 
 5556-4.3 buoy 
 1, the outer diameter of 710mm inner diameter of 440mm 
 2, in the fresh water bearing not less than 14.5kg of iron 24h years 
 3, with the quality of not less than 4.0kg