The cameras in this collection are all analog. This means they are not High Definition or 720p or 1080p. There are still many uses for analog cameras. Primarily when using portable analog DVRs. Analog DVRs take up much less storage space on an SD card compared to HD cameras. A person may be able to store up to 30 days of footage on a 64 gb SD compared to only a few days when using an HD 1080p camera. Universities doing animal studies, Police doing outdoor surveillance, companies performing traffic and pedestrian counts normally use analog cameras.