The product is a pack of 500 green polyethylene snap-it vial caps with pre-slit PTFE septa, specifically designed by Thermo Scientific for sealing vials in a laboratory or medical setting. These caps provide a secure seal to prevent contamination or evaporation of the contents inside the vials. The pre-slit PTFE septa ensures that the cap can be easily attached and removed, making it a convenient and efficient solution for ensuring the integrity of samples in research or medical applications.