Bare metal: 5.5g/piece (not charged) Battery: 3 g / piece Product specification: 60×30×10mm bag specification: 7×12cm Bag full set: 13g / piece (with battery) 10g / piece (without battery) Color: black- and white- pink green blue colors Date Wheel Boys Watch Senior Alert Device No Monthly Vehicle for Kids Vsm550 Life Alert Necklace No Monthly Track Kids Location Kid Emergency Phone Car Fix Boy's Watch Suitable For 11 And Above Can Be Used.Android Phones: Android 8.0 And Above, Bluetooth 5.0 And Above. This Loss Device Is A Product Based On The Latest Bluetooth 5.2 Low-power Technology. Through The Use Of APP Software And Mobile Phones And Other Mobile Devices For Bluetooth Connection, It Can Bundle The Items And Valuables (such As Keys, Handbags, Etc.) The Effective Use Distance Of The Device Can Reach 25 Meters In A Wide Range. The Button Battery CR2032 Can Be Easily Purchased In Major- Supermarkets. The Brand Battery Can Work For More Than Half A Year. At Present, In Order To Increase The Battery Life Of Mainstream Android Models, The System Has Been Optimized To Varying Degrees, And Will Automatically Clean Up The App Running In The Background. When Using The Loss Device, The App Needs To Be Set And Protected In The System To Realize Normal Operation. Although The Setting Steps Of Android Phones Of Each Brand Are Different, They Are Almost The Same. First Check The Power Saving Mode Of Your Mobile Phone System, And The Loss Device App To The White List Or Protected Program To - The / Loss Device App From Being Shut Down By The System And Causing False Alarm.