But how much buoyancy has this harness?
The page states that the harness is ISO12402-5 certified, therefore it is a 50 Newton (11 lbs) "flotation aid", not a "lifejacket". It is not USCG certified (and does not meet the 70N / 15.5 lbs minimum buoyancy required). It does not fulfill the requirement of racing rule 40 in the United States.
Regards,
Eric