●CHIME WITH TWO SOUNDS: Classic two-note “Ding Dong” sound for the front door button and has an additional connection with a separate "Dong" for the rear or side door ●DIMENSIONS: Cover: 8. 25” L x 5. 5” W Base: 6. 63” L x 4. 75” W ●16-VOLT, 30VA DOORBELL TRANSFORMER: For powering up to three hardwired doorbell chimes or modern smart video doorbells ●ELIMINATE ISSUES CAUSED BY UNDERPOWERED TRANSFORMERS: A lack of power, connection issues, low quality video resolution, and low chime volume may be an indicator of an underpowered transformer ●??PLEASE NOTE: Customers have mentioned that using model CHM3D and a 16V/30VA transformer WITH a video doorbell will work, but we cannot guarantee this.