Kirkland Ultra Clean Laundry Detergent Pacs are conveniently pre-measured to contain the right amount of powerful concentrated detergent needed to fight tough stains, they dissolve completely in hot or cold water, leaving nothing behind but clean, every time. All pacs are easy to use and safe for all washing machines. Ultra Clean Pacs are high efficient, non effiency, front loader, top loader compatible. 1 pac = 1 medium load of laundry. How to use Kirkland Signature Ultra Clean Pacs: (1) Dry hands before handling (2) Do not unwrap or cut open pacs (3) Add pac(s) into washing machine while filling, and then add laundry. Use 1 pac for most loads. Use 2 pacs for heavily soiled loads (4) For HE machines, add directly to the washing machine drum, then add laundry on top. DO NOT put the pacs in the drawer (5) Keep container sealed between uses.