Sennheiser CX Plus Instruction Manual page 38

Specifications
38 | CX Plus True Wireless
Bluetooth
Version
Transmission frequency
Modulation
Profiles
Output power
Codec
Device name
Bluetooth 5.2 compatible, class 1
2,402 MHz to 2,480 MHz
GFSK, π/4 DQPSK, 8DPSK
HFP, AVRCP, A2DP
10 mW (max)
aptX®, aptX adaptive®, AAC, SBC
CX Plus True Wireless