Feature:1.It has 2 channels,with 2 keys,can be used for 1 or 2 channels.Note:1.It has no factory default,so it can not be used when you receive it.you need to learn and link with the original relay/receiver who is also 433MHz.2.Before buying,please confirm if the operating frequency, chip type and vibration resistance of your transmitter are in accordance with ours.3.How to confirm if the operating frequency, chip type and vibration resistance of the transmitter are in accordance with the receiver/relay?Connect the receiver board to power it, the power indicator on the receiver board will turn green, please press the transmitter, if the signal light on the board shows the tomato light, it means that your transmitter is consistent with our receiver; if When you press the transmitter, the signal light does not perform any operation (will not light up), which means that your transmitter cannot be used for our receiver..How to link this transmitter with your receiver?1. Pay attention: this 433MHZ transmitter only can be used with the learning code receiver, can not apply to the Rolling code or Fixed code receiver2. The 2260 chip remote control transmitter, the default resistance value is 824, can ONLY match the 2272 chip receiver;3. While meet the above conditions, you can link with the receiver and use it according to your own learning code receiver's learning method.SpecificationColor: Red & BlackMaterial: ABS & MetalOperating Frequency: 433MHzWorking Current: 10A,12V;Battery:12V 27A(not included due to Custom Inspection)Received Frequency: 433MhzReceiving Sensitivity: -100dbTransmitter Size: 52 x 40 x 12mm / 2.05x1.57x0.47Inch (LxWxH)Weight: 30gPackage include:2 x Transmitter (Battery is not included,You can buy 12V 27A batteries locally for use.)