Specifications:

Number of channels: 4
Size: 28.5 x 15 x 7.4mm
Weight: 4.7g (without shrink wrap)
Sensitivity: about 2.0uV
Selectivity: ±8kHz at 65dB down

Takes a micro crystal.

Specifications:

Number Of Channels : 6CH
Frequency:FM-35Mhz
Size : 35x22x10 mm
Weight : 7.5gram
Antenna Length : 800mm
Operating Voltage : 4~6V
Current Drain : 9mA
Range: 800M

High adjacent channel selectivity and interference rejection
No servo jitter when the transmitter is switched off

Specifications:

36*22*8.2mm
Weight: 7.3g
Sensitivity: 2.0µ
V Selectivity: ±8kHz at 65dB down
Number of channels: 1-8
Filtering: Dual turned RF circuitry
Filtering: Dual 4 element ceramic filter
Filtering: DSP filtering in MCU with mild algorithm
Shift polarity: Positive or negative (auto-detect)
Case: Shrink wrap Operating
Voltage: 4.8V~6.0VDC Operating Current 11mA
Modulate: FM/PPM(pulse position modulation)

Specifications:

36*18.7*8.2mm
Weight: 6.8g
Sensitivity: 2.0µ
V Selectivity: ±8kHz at 65dB down
Number of channels: 1-6
Filtering: Dual turned RF circuitry
Filtering: Dual 4 element ceramic filter
Filtering: DSP filtering in MCU with mild algorithm
Shift polarity: Positive or negative (auto-detect)
Case: Shrink wrap Operating
Voltage: 4.8V~6.0VDC Operating Current 11mA
Modulate: FM/PPM(pulse position modulation)