![Amazon.com: MDD 4TB 64MB Cache 5900PM SATA 6.0Gb/s 3.5" Internal Surveillance CCTV DVR Hard Drive (MD4000GSA6459DVR) - w/ 2 Year Warranty : Electronics Amazon.com: MDD 4TB 64MB Cache 5900PM SATA 6.0Gb/s 3.5" Internal Surveillance CCTV DVR Hard Drive (MD4000GSA6459DVR) - w/ 2 Year Warranty : Electronics](https://m.media-amazon.com/images/I/61y9UTDichL._AC_SS450_.jpg)
Amazon.com: MDD 4TB 64MB Cache 5900PM SATA 6.0Gb/s 3.5" Internal Surveillance CCTV DVR Hard Drive (MD4000GSA6459DVR) - w/ 2 Year Warranty : Electronics
![Amazon.com: Surveillance Hard Drive 4TB Internal SATA 3.5, HDView Security DVR NVR Compatible : Electronics Amazon.com: Surveillance Hard Drive 4TB Internal SATA 3.5, HDView Security DVR NVR Compatible : Electronics](https://m.media-amazon.com/images/I/81txRFmZdVL._AC_SX466_.jpg)
Amazon.com: Surveillance Hard Drive 4TB Internal SATA 3.5, HDView Security DVR NVR Compatible : Electronics
![Amazon.com: WL 2TB 64MB Cache 5400RPM SATA III (6.0Gb/s) 3.5" Internal Surveillance DVR Hard Drive - w/ 1 Year Warranty : Electronics Amazon.com: WL 2TB 64MB Cache 5400RPM SATA III (6.0Gb/s) 3.5" Internal Surveillance DVR Hard Drive - w/ 1 Year Warranty : Electronics](https://m.media-amazon.com/images/I/61tkue5-T2L._AC_SS450_.jpg)
Amazon.com: WL 2TB 64MB Cache 5400RPM SATA III (6.0Gb/s) 3.5" Internal Surveillance DVR Hard Drive - w/ 1 Year Warranty : Electronics
![How to Calculate the Recording Days of Storage Capacity for Hard Drive(HDD)- CCTV Security Video Surveillance DVR & Camera Manufacturer How to Calculate the Recording Days of Storage Capacity for Hard Drive(HDD)- CCTV Security Video Surveillance DVR & Camera Manufacturer](http://www.esyncctv.com/web/userfiles/article/ARTICLEimages/HDDinDVR.jpg)