[Easy to Use ]We have made transmitter and receiver working and test it it,when you it 't need to do anything ,just install it. STRONG SIGNAL--Adopts RF technology , signal can pass through walls, floors and doors, steadily control receiver from any place within a distance. Max range is up to 984ft with no obstacle. High Power Load: With 30A relay of receiver , which can load high-power electrical appliances to long-term stability control. [Security Control]:Learning code has high-level security for low repetitive rate and re-learn mode, it can delete the old code and re-learn a new code,when a remote control lost. So you could always control of it. [Easy to Use]:Extremely easy to setup, learn, relearn and control. Stable and performance, high receive sensitivity.Configuration of two remote controls(alkaline 12V 23A batteries),more flexible use. Wide Application:It is mainly used in ,electric doors,windows,gate,industrial control and security industry and other fields. color:White Material:ABS size:8.53 x 4.37 x 3.02 cm Package Contents: 1 x Receiver module (KR2201B) ( include Shell ) 2 x Remote Controls (include battery) Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.