We recommend a Brassiere or Vest be worn under the Econo Guard. To select correct guard size refer to chart. Measure chest size under bust . Cup size should be the same as your standard brassiere. We recommend the brassiere or vest be of the synthetic textile type to allow moisture to move and evaporate.
Evaporation is natures own body cooling method.
If the back strap does not hold the guard firmly then try the next size smaller guard or a thicker brassiere underneath.