The HD7-915RCP-PM-BLK is the Pole Mount Bracket for the HD7-915RCP, a Circularly Polarized, Heavy Duty, High Vibration Panel Antenna with 7 dBic maximum, and a frequency range of 902-928 MHz.
The antenna covers the frequencies needed to perform on ISM; The 902-928 MHz band operates on networks in the US.
For more details, see the HD7-915 Spec Sheet.