Stygobiont species show common. typical traits derived from their adaptation to subterranean life. Due to the general absence of light in cave environments. the majority of them are eyeless. https://www.roneverhart.com/Western-Digital-Ultrastar-DC-HC570-WUH722222ALE6L4-0F48155-22TB-7-2K-RPM-SATA-6Gb-s-512e-SE-3-5in-Refurbished-HDD/