Our Pet Training Collar Receiver Is Compatible With Our Dog Fencing System; When Your Dog Approaches The Boundary, The Signal Causes The Dogs Collar Receiver To Deliver A Warning Beep First; If Your Dog Continues Closer To The Boundary, The Collar Will Issue A Mild Shock; If Your Dog Continues Further, The Collar Will Issue Stronger Shocks Until Your Dog Returns To Within The Boundary You Have Set Up; Your Dog Will Naturally Seek To Avoid Correction, And Is Content Staying Within Established Boundaries; Keep Safe In Limited Space. (Only Collar, Fencing System Not Included); Product Type: Electric Dog Collar Receiver; Color: Black; Material: Abs; Type: 4Lr44 6V; Runtime: 10 Days; Fit For Dogs: Fits Dogs 4Lbs+ With Neck Sizes From 7.5In To 17.92In; Collar Strap Length: 45.5Cm/17.92In; Item Size: 6.5X3.5X3Cm/2.56X1.38X1.19In; Item Weight: 56.5G/0.12Lbs