DS80HKAI-VX1 Enterprise Hard Drive Key Features  Industry Standard 3.5-inch 26.1 mm Height Form Factor  7200 rpm Performance, SATA 6 Gbit/s Interface  Industry-standard 3.5-inch form-factor  Designed for 24x7 operation  256 MB Cache buffer helps to smooth video recording and guard against frame drops  550 total TB transferred per year workload rating

HIKVISION 8TB PURPLE SATA INTERNAL HARD DRIVE - 8TB , 6 GB/S , Cache MB