Make your phone line Never Busy with a Flashing, Loud Ringer Box Even When The Phone Is OFF the Hook! Loud Ringer when a call comes in Operates with Simple Connection to Phone Line (Easy to install) Visual Incoming Call Ringer with Flashing Light Indicator (Allows to visually 'See' the phone ring. Great for those that have hearing difficulties to know the phone is ringing) Make your phone line Never Busy with a Flashing, Loud Ringer Box Even When the Phone Is OFF the Hook! The No Busy unit will allow the phone line to remain open to calls even when the handset is not properly set down, or in the case of cordless handset, switched off. Without the No Busy unit, the phone line would remain busy, and unable to receive incoming calls. FEATURES: -Auto Hang Up Detectors and timers (The unit knows if the phone is not hung up) -3 Ring Volume Adjustable by Switch (Allows for the ringer volume to be set to your specification) -3 Ring Tones Pitch Adjustable by Switch (Set the sound of the ring from a low to a high pitch to fit your preference) -Visual Incoming Call Ringer with Flashing Light Indicator (Allows to visually 'See' the phone ring. Great for those that have hearing difficulties to know the phone is ringing) -Operates with Simple Connection to Phone Line (Easy to install) -In and Out RJ11 Jacks for Line and Telephone Provide for Quick Installation (Plugs in between phone and the wall jack, no extra jack needed) -Wall Mountable (Save counter space by mounting on the wall) -Size -- 4" Width x 4" Length x 2 1/2" Height (If unit does not release line - see note regarding switch settings on bottom of unit)