Specifications:

HC-12 SI4463 wireless microcontroller serial, 433 long-range, 1000M with antenna for Bluetooth

Supply voltage 3.2V ~ 5.5V. (If you want to work in the module launch state for a long time, it is recommended when the supply voltage exceeds 4.5V series with a 1N4007 diode, to avoid heating module built LDO)
Default communication distance (open test): about 600m (adjustable to achieve the maximum communication distance of 1000m, the air baud rate 5000bps).
The default idle current: 16MA (modules in different operating current of the different operating modes).
Module Size: 27.8mm × 14.4mm × 4mm.
Operating frequency range (433.4-473.0MHz, up to 100 communication channels) Maximum 100mW transmit power (can be set)
The module supports software upgrades. (We provide customers with software upgrades)
The default factory settings: operating mode FU3, baud rate 9600bps, communication channel CH001 (433.4M).

PS: HC-11 can not be connected to communicate with the HC-12, they work independently, in pairs.