The VC-Pro is portable and compatible on all telephones. Simply attach the acoustic coupler to your telephones handset, adjust the 16 settings by turning the selector clockwise. It has 0 being your normal voice, the high settings will increase the pitch and low settings will decrease the pitch. Specifications: ¥ Professional grade voice changer ¥ Lightweight and compact ¥ Powered by a 9V battery, not included Includes: ¥ Voice changer ¥ Mouth peice coupler SIZE: 6" x 2 7/8" x 1 1/4" Ships only to verified credit card billing address. Ships to USA addresses only. Does not ship by air