HPE option part number for the product described as 2.4TB SAS 12G Enterprise 10K SFF (2.5in) SC 512e Digitally Signed Firmware HDD. Further details below.
The 881457-B21 is a small form factor 2.5 inch HPE SAS hard drive, mounted in a universal hotplug smart carrier. This is a genuine HPE hard drive with HPE firmware and is specifically for use in certain HP Proliant servers and storage arrays. This is not a third party or generic drive. A sampling of compatible machines is found below but that list not complete.