Cisco Aironet Power Injectors provide inline power for Cisco Aironet 1100 and 1200 series access points and 350 series access points and bridges. Three models are available:
AIR-PWRINJfor 350 Series access points and bridges.
AIR-PWRINJ3for 1100 and 1200 Series access points.
AIR-PSINJSYS1200for 1200 Series access points.
Note** The 1100 and 1200 series power injectors can be used with 350 series devices, but due to the higher current demands of the 1100 and 1200 series, the 350 series power injector cannot be used with 1100 and 1200 series devices.
From this doc;
Installation Instructions for Cisco Aironet Power Injectors