Safety holder with alarm function to prevent children from getting lost or leaving belongings behind. - Product Name: Smart Safety Holder - Functions: Prevents children from getting lost, anti-theft alarm - Communication Distance: Approximately 25m - Compatible OS: Android, iOS - Size: Approximately 13.0 x 21.0 x 2.5cm - Material: ABS Purchased around September last year to prevent my mother from forgetting her smartphone, not for children. She often forgets her smartphone, making it impossible to meet up, missing the Shinkansen, going shopping, leaving it unattended near the deep fryer and getting it messy in the kitchen, or leaving it in her bag on the floor in a store. After searching for solutions and consulting with her father, we found this. I am selling this because despite my efforts, she lacks awareness and effort. Please note that the app needs to be left running in the background with Bluetooth constantly turned on. According to the manual, the smart tag also has functions to make the phone ring and send voice messages. I don't think the battery drains very quickly. I will include the manual, but please let me know in the comments if you don't need the box. Thank you for looking.