I have had 4 of these cameras operating on the exterior of my home now for over 2 years. I have never had any problems with their operation, which is 24/7. I installed a 128 Gig micro SIM card in each one when I bought them, and they have all worked flawlessly, and I have yet to exhaust the memory limit on any of the SIM cards. The only issue I have with them is the sheer volume of videos that I can retrieve at anytime and anywhere’s. it is impossible to review all the hours of video that are recorded and saved. They are motion activated, and the videos are 1080, which is more than sufficient. Also, every second is time stamped, and I can send snapshots or videos, and save them to photos, or email them. It is a great product. Each camera transformer is connected to a 120 VAC power source, so that there are no batteries to replace, and they only go offline if there is a power outage, or if I loose my WiFi.