Both eufy baby monitors on this page work with Wi-Fi off, sending video only to the parent screen, and with Wi-Fi on, adding app viewing that you can share with up to 5 family members. Three questions narrow the choice between them: do you want to check in from your phone, how much do you need to see at night, and will the camera move between rooms or travel with you.
Do you want to check in from your phone?A non-Wi-Fi monitor keeps the video between the camera and the parent screen but cannot reach your phone, and a Wi-Fi monitor works from anywhere but depends on your home network. You do not have to choose between them with eufy: the eufy Baby Monitor E21 and the eufy Baby Monitor C10 both show the camera on the parent screen with Wi-Fi off, and you can turn Wi-Fi on to watch in the eufy Baby app while you are out. Since phone access works the same way on both, choose by where the camera will live.
How much do you need to see at night?First decide what you need at night: a view clear enough to tell whether your baby is asleep, or the option to zoom in on your baby's face while they sleep. The eufy Baby Monitor E21 suits a closer look, with a 4K camera and 8× zoom. The eufy Baby Monitor C10 has a 2K camera and 4× zoom, which covers a basic check at night, and it costs less. The specs differ, but what you see at night also depends on factors such as how far the camera sits from the crib and night vision, and the camera's resolution is not the same as the parent screen's, so camera specs cannot promise how clear the picture will look at night.
Will the camera move between rooms or travel with you?If naps happen in different rooms or you travel, choose the eufy Baby Monitor E21. Its camera has a 5,000mAh battery that lasts about 9 hours, or about 5.5 hours with night vision, so it works where there is no outlet nearby, and you recharge it between uses. During a power outage, the E21 camera keeps running on its battery and connects to the parent screen without your router, but app viewing stops if your router or internet goes down. If the camera stays in one nursery near an outlet, the eufy Baby Monitor C10 fits and costs less: its camera must stay plugged in, and its parent screen runs up to 12 hours on a charge.