This is 1 case of 12 BlueStar Refill Kits (BL-501). That’s 48 total uses. Save almost $100.00 compared to buying just 1 at a time. BlueStar® blood tracking reagent will pick up blood droplets unseen by the naked eye and make them glow bright blue in low light conditions. Works in the rain when blood trails disappear. BlueStar finds HEMOGLOBIN, which the eye of humans can not see. No matter how much rain or what the terrain is BlueStar will find blood if it is there.