Set of 2 baby alarms. The set is 6500 yen, but individual units are available for 4500 yen each. If you want to buy one, please let me know in the comments. Used for 3 to 11 months. The batteries still have some charge, but I think they are low. It might be better to replace them for peace of mind. The BabySmile E-202 with a high-sensitivity sensor allows you to safely monitor your baby's sleep. - Brand: BabySmile - Model: E-202 - Function: High-sensitivity sensor - Target age: 0 months and up - Other features: Sleep monitoring function Thank you for looking.