This product includes 160 ul of 10 x Buffer HT1, 84 ul of 10 x supercoiled plasmid DNA, 3 ul of 4500 x Dye H19 and 500 ul of 10 x H19 dilution buffer. It is for 20 DNA relaxation assays in a 96-well plate format or 40 assays in a 384-well assay format. Human topo I enzyme in not included and can be purchased separately.