...I'm not sure in just what position, or, under what circumstances the manufacturer refers to, because in my trial with the product both my children ( a girl 2yrs. old and boy 4yrs. old) were able to tip face forward rather easily. That said, though, the suit keeps kids upright and comfortably afloat while in a relaxed position. The Swimsafe™suit has no floatation in the upper arms and thigh areas so it allows flexibility for arms and legs. Nonetheless, Swimsafe™ floatsuit features a patented neck roll and unique front and back buoyant panels that are slim and anatomically creased for natural movement. The panels are compartmentalized in smooth comfortable liners that are comfortable against the skin. The back zipper keeps child from loosening or removing the suit. The fit is good but not perfect, so if your child is just within the size range and a bit small for the suit, the floatation panels will rise and push the suit up over the chin and face somewhat, depending on position and movement of the child.
Material is lycra which is lightweight and form fitting; great for very warm climates. Remember, though, lycra pills and picks easily so it can lose it's smooth , new appearance quickly, especially on the chest and thigh areas as kids climb in and out of a poll etc.
Children are particularly susceptible to harmful ultra violet rays. Swimsafe™ floatsuit covers skin from mid-bicep to mid-thigh so it does double duty as a high quality Ultra Violet Protection swim suit and has a U.P.F. rating well above 40, so Swimsafe float suit protects from the suns harmful rays too. 
CAUTION: Swimsafe™ Floatsuit must NOT be used as a lifesaving device rather it is a swimming aid and must be used as such and always in conjunction with proper adult supervision.Do Not leave children unattended. Neither TESCO Enterprises (The Eclectic Sales Co.) nor, the manufacturer will be held responsible for any accidents.