Shrinkage? This concentrated wash-in treatment softens the internal fiber structure at a sub-molecular level. Perfect for gear that somehow shrank over the winter. Provides up to one full size increase. Uses only two capfuls in the washing machine, so supply will last for years. After washing immediately wear damp for 20 minutes to allow the momentarily elasticized fibers to re-conform to your (ahem...) current girth before putting it in the dryer, which causes them to 'set'. For all Nylon, Polyester and other synthetic fiber textiles. Not for electric garments. Expanded suits should not be worn in rainy or damp conditions (fibers go back to original size within minutes. A choking/breathing hazard). From H. Held Industries. 5 oz bottle.