USB-C Rechargeable 0.4Wh Li-Poly battery delivers up to 6 months per charge. 80 dB+ Audible Alert Loud enough for easy indoor location. 304 Stainless Steel Construction Engineered to withstand up to 15° structural flex. Ultra-Thin 0.051 in (1.3 mm) Profile Slim design fits seamlessly in wallets. Built-In Phone Finder Trigger your iPhone directly via Apple Find My network. Apple Find My (MFi Certified) No third-party app required.