This antenna from Delock enables the use of the 868 MHz band both indoors and outdoors.

Connection: 1 x SMA connector
Frequency range: 860 - 870 MHz
ZigBee 868 MHz, Z-Wave 868 MHz, LoRa 868 MHz
Antenna gain: 3 dBi
Impedance: 50 Ohm
Efficiency: 45.91%
VSWR: 1.5
Polarization: vertical
Operating temperature: -20 °C to 65 °C
Housing material: ABS
Color: black
Antenna length: approx. 13.5 cm

System requirements:
Device with a free SMA socket.