iPhone XS Max A1921 (T-Mobile) Logic Board with Paired Face ID Sensors
Includes the paired earpiece speaker and front-facing camera assemblies.
Face ID sensors that are part of the earpiece speaker and front-facing camera assemblies are paired to the logic board in an iPhone XS Max. To retain Face ID will functions a logic board must be replaced along with its paired components.
This logic board is "locked" to T-Mobile. If you wish to stay with your phone's original service provider you must replace the logic board with one locked to the same provider.