The successor to the T-1 Telephone-HT20 telephone is a more advanced model with a popular design that is composed of monotone and simple lines while still providing a lamp to notify you with messages and phone calls. Specifications: Line Jack: Uses RJ11USOC line jack; Dial Method: Tone (line only); Power Supply: Power Supply from phone line; Usage Environment: Temperature: 32 - 104°F (0 - 40°C); JATE: Jacob Jensen HT20 A15-0055005 (*This unit has a direct current resistance of 354 Ω max). May not be used due to connection conditions. Features: Volume adjustment / SOS one-touch dial (shortened dial in 1 place) / Redial function (※erases after 5 minutes) / Message weighting function (High Voltage 90 V / Lucent low voltage system compatible) / Wall installation compatible *Fixing screws are not included. Size: Approx. 2.0 x 7.9 x 2.0 inches (50 x 200 x 50 mm) (when mounted on the wall): Approx. 2.0 x 7.9 x 3.5 inches (50 x 200 x 90 mm) (when installed on tabletop); Material: ABS resin; Design: Jacob Jensen; Color: Black