This is the field effect transistor (FET) you need to replace your mCP X main motor FETs. It has slightly higher output than the standard 2.3A replacement FET and has lower internal resistance for more efficient operation.
The FETs should be replaced as a pair.
This is the gyro used in the MCPX V2, MSR X, mQX, 130X, MCPX BL, and Nano CPX. It is also used in many other planes and helicopters.