1. And Beep Saves The App: Key Finders That Make Noise Work Via Radiofrequency And Need No App. Simply The Coded Button On The Transmitter, And The Corresponding Receiver Beep And Flash All At Once, Helping You To Find The Item Easily You Attach It To. While The Phone Dies For The Key Finder Locator App Every Now And Then, But The Wireless Key Finder Have 12 Months Long Standby Time 2. Loud Beeper, 120ft Remote Distance: With As Loud As 75-85db Beeping Volume, Even People With Poor Hearing Are To Locate The Lost Items Easily. Wave Of The Tracking Device For Keys Can Penetrate Through Walls, Floors, Cushions, Etc. Helping You Track Down Items As Far As 30-50 M(Tested In Open Area). The Distance Being Well To Cover Whole Area Of Your Apartment, It' S Very Helpful As A Lost Keys Tracker, Or Tracker For Wallet, Phones, Glasses And Pets. 3. Indoor & Outdoor Use: With The Portable Size And Light Weight, The Tracker Tags Are Suitable For Both Indoor And Outdoor Use, Like When You Want To Call Back The Pet From The Yard Or Find Your Luggage In Travel. You Can Stick The Receiver To The Tv Remote Control, Glasses, Ear Pods, Or Attach It To Keychain, Backpack, Pets, Kids, Etc. For Mobile Phone, A Protective Cover And Lanyard Is Needed. For Wallet, Just Cast The Receiver Inside. 4. Handy And Considerate: The Transmitter Is Self-Standing, No Extra Holder Needed. Simply Set The Find My Keys Device On Top Of The Table Or Other Places Where You Remember Easily. 2 x AAA Batteries Are Needed For The Transmitter. (Battery Is Not Included) Beeping Sound: 75-80db Receiver Dimensions: 39mm x 35mm x 8mm Transmitter Dimensions: 127mm x 45.5mm x 14mm Working Frequency: 433.92mhz Operating Voltage: DC2V-3.6V Operating Temperature: -10-60 Circuit Board Material: Double-Sided FR4 Industrial Grade Board Receiver Sensitivity: Less than -113 dbm Working Distance: 30-50m (In Open Area) Transmitter Battery:2 x AAA Batteries (Batteries Not Included) Battery For Each Receiver:1 x Cr2032 Battery(Battery Included) Notes: 1. Sound Is Louder If You Keep All Doors Open When Finding Items In Other Rooms. 2. Actual Standby Time Depends On Use Frequency And Your AAA Battery Power Volume. 3. Please Set It At Places Beyond The Reach Of Children. 4. Two Sets Interfere With Each Other If Used Together. Make Sure To Use 2 Sets Separately. Color:Black Material:ABS Package Contents: 1 * Transmitter (without 2xAAA batteries) 4 * Receivers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.