Vaultek Nano Key 2.0 Biometric with Rechargeable Lithium Battery Includes: Adhesive Backed Mounting Bracket (1) Micro- USB Charging Cable Product Features Compatible with Bluetooth 2.0 safes only Instant access with one simple touch Mount anywhere with the included bracket and mounting tape Biometric scanner can store up to 20 fingerprints for secure access and features a range of up to 20 feet. Built-in rechargeable battery provides 3 months of standby time and can be recharged in 2.5 hours. Product Specifications External Dimensions: 1.8 Diameter x 8 Tall Battery Life: 3 months on a single charge Range: 20 feet (varies per model) Biometric Storage Capacity: 20 Unique Fingerprints