Quantum ST21S012 Rev 02-C 3.5 SCSI Hard Disk Drive. HSC Electronic Supply Terms & Conditions. Additional charges may apply in this case.Will Call is encouraged for Silicon Valley customers. Dept of Commerce laws are strictly adhered to. Do not ask for any changes to tariff codes or product value. Credit cards require approval on a case by case basis. HSC Electronic Supply 3500 Ryder St.