Yealink EXP38 IP Phone Expansion Module Type: Expansion Module LEDs: 38 programmable keys each with a dual color LED Dimensions: 5.20 x 5.63 x 1.65 Weight: 0.56 lb. Temperature: max 60 degree Humidity: 10~95% Specifications: 2 x RJ-12(6P6C) ports for data in and out Power adapter: AC 100~240V input and DC 5V/1.2A output