No external power supply, directly with the telephone line current work. 30cm x 20cm x 10cm (11.81in x 7.87in x 3.94in). The item "Retro Wall Mounted Telephone Corded Phone Landline Antique For Home Hotel saloon" is in sale since Tuesday, September 11, 2018.This item is in the category "Consumer Electronics\Home Telephones & Accessories\Corded Telephones". The seller is "budd_band" and is located in Guangdong . This item can be shipped worldwide.