Check the listing for details. Low cost ASK transmitter module DRA889TX-S --- 4pcs. Condition: New. Listed at 2.98 USD. Features: * Frequency Range: 433.92MHz * Output power: 11dBm @ 3V 16dBm @ 5V * Tx current: 24 @ 3V * Temperature: -20~+70C * Supply voltage: 2.2~5.5V DRA889TX-S is a type of low cost ASK transmitter module which is designed with SAW resonator and PA for cost-efficient solutions. It can be used in wireless door opener, robot control, security alarm and related applications. Please note that when DRA889TX-S is supplied with higher voltage than 5.5V, the output power of it will also be increased but the distortion of wave will also be worse. Unless users are very sophisticated in ASK modulation and can pick out the effective data easily, we don't recommend users to use it in higher voltage. The price includes 4pcs of DRA889TX modules. For more details on using this product, please check the wireless module page on the website of DORJI.