What does 100n signify on life jackets?

The 100N life jacket

The 100N life jacket is for those who may have to wait for rescue but are likely to be in sheltered, calm water. It may not have sufficient buoyancy to protect someone who is unable to help himself or herself and may not roll an unconscious person on to his or her back, particularly someone in heavy clothing.

The 150N life jacket

The 150N life jacket is for general use on coastal and inshore waters when sailing and fishing. It is intended for general offshore and rough-weather use when a high standard of performance is required. It should turn an unconscious person onto his or her back and requires no subsequent action by the wearer to keep his or her face out of the water. Its performance may be affected if the user is wearing heavy and/or waterproof clothing.

The 275N life jacket

The 275N life jacket is recommended for offshore cruising, fishing and commercial users. It is intended primarily for extreme conditions and for those wearing heavy protective clothing that may adversely affect the self-righting capacity of other life jackets. It is designed to ensure that the wearer is floating in the correct position with his or her mouth and nose clear of the surface of the water.