Changed from Yu-Packet Post to Nekopos (anonymous delivery). Purchased in June 2024 and used for about 2 months total: during the newborn stage and for about a month when the baby started rolling over but couldn't roll back. The smartphone alerts sound at a volume that will definitely wake you up, even during sleep, if there are any abnormalities in breathing, temperature, or position. As a first-time parent, I was constantly worried about whether my baby was breathing properly and if their temperature was normal, and I couldn't sleep soundly at night. But thanks to this sensor, I was able to rest a little easier. It's in excellent condition, like new, with no noticeable scratches or stains. The battery was dead, so I put in a new battery to check the operation, and then immediately removed it. I'll include one unopened new battery, for a total of two. All other accessories are included. I will carefully package it and ship it via Yu-Packet Post. [Body Size] Size/Length 40x Width 40x Thickness 10mm, Weight/Approx. 12g. Set Contents/Accessories: Main unit, mounting ring for the main unit, battery installation pliers, coin battery CR2032 x2, skin tape 4 sheets - Know the baby's abdominal breathing movements: Unlike traditional video cameras and audio monitors, you can easily and safely monitor your baby's abdominal breathing movements, sleeping position, and body temperature using your smartphone. The dedicated app will sound an alert when the baby's movements are weak. - Baby's rollover reminder: The Sense-U baby sensor monitors the baby's sleeping position in real-time and sounds an alarm on your smartphone when the baby is sleeping on their stomach. - Protect your baby from overheating & cold reminders: The smartphone will sound an alarm if the temperature around the baby's abdomen is too high or too low. - Uses low-power electromagnetic field-free Bluetooth: Uses Bluetooth's ultra-low power technology, with low electromagnetic field radiation and is healthy (signal strength is equivalent to 1/1000th of a mobile phone), and the straight-line communication distance is 15 meters. When the device enters the effective communication range, it will automatically reconnect. By using the separately sold Sense-U base station, you can check the baby's condition from anywhere with voice and light notifications. - General medical device Medical device notification number: 13B2X10508000101