Extra-loud Telephone Ringer Phone Ring Amplifier Ringing Bell Sound Features: This product is made with superior electronic material, designed by high technology. It has preety appearance,stable function,loud and clear sound,suitable for using in the noisy places. Connected it with the telrphone line, no other electric power is needed. It helps the hearing-impaired, the heavy sleepers, and people who love wandering far from their phones. Note: 1.Transition: 1cm=10mm=0.39inch 2.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Size: about 9.3cm long Shipping color: white Quantity shipped: 1