The external hard drive from OWC has a capacity of 4TB and it is SSD, a modern hard disk technology that offers high speeds, reliability, lower power consumption, weight, and size compared to HDDs.
Assuming that the average size for a photo, an MP3, and a video is 2MB, 4MB, and 500MB respectively, then This external hard drive can store approximately up to 2,000,000 photos or 1,000,000 MP3s or 8,000 videos.
If size is 2.5", it is the classic size of an external hard drive. If size is 3.5", it is usually found in high-capacity drives that require additional external power. If size is 1.8", it means it is a small-sized disk, easy to transport. If size is M.2, it means it is a small-sized disk, easy to transport. If size is Multi-Bay, it is a large-sized and high-capacity type. Suitable for storing and backing up large files. Not recommended for frequent movements due to its weight. If extern_power is true, it will require power supply from an outlet. Otherwise, it does not need power supply from an outlet to operate, just connect it to your computer with the corresponding cable

• Capacity: 4000GB
• Interface: Thunderbolt 3