Features:The product working frequency according to national regulations, and noharmful electromagnetic interference, is compliant with the globally applicationsstandard. Far wireless remote control distance is up to 200m, has a good quality andstable signals, suitable for both household and industrial use. The outside doorbell have long time service with 4 batteries inside(Not included), workingmore than half a year. Adjustable voice volume and changeable ring type, reminding you the comingof your guests by lovely songs. Big and adjustable speaker, clear voice, can be used as mobile interphone. Made of eco-friendly ABS material, pollution-free, hard-wearing, scratch-resistant. Equipped with anti-interference system, avoid interferences outside orbetween neighbors. Simple and easy wireless installation with adhesive tape, save troubles andmoney. Specification:Condition: 100% New BrandMaterial: ABSColor: Silver + BlackOutside Doorbell Working Power: 4 x AAA Battery(Not included)Inner Doorbell Working Power: Rechargeable Li-ion Battery(Can be charged by USB cable)Wireless Distance: 200MOutside Doorbell Working Time: > 6 MonthsInner Doorbell Working Time: 48H (Suggest always plugged into thepower supply)Working Temperature: -20~55Working Frequency: 467.6375 MHZSize: Approx. 100 x 62 x 14.8 mm /3.94 x 2.44 x 0.58 inchWeight: Approx. 156gPackage Included:1 x Outside Doorbell1 x Inner Doorbell1 x User Manual1 x Doorbell Label1 x USB Cable for Charge1 x Screwdriver2 x Adhesive Tape with GlueNote:It's not waterproof. Adjustvoice volume and change the ring type by the small black button. Please use screwdriver to unscrew battery cover to change the battery when the outdoor bell run out of batteries. It is recommended that to keep indoor bell charging in power supply after use. Please allow slight deviation for the color and measurement. Thanks for yourunderstanding.