This mounting bracket is used with roller shades that have the Rollease Cassette 120 system. That cassette measures 3 7/8″ tall and 4 7/16″ wide.
Also compatible with 2″ Versarail wood blinds that operate with a clutch and cord loop.
Rollease part number V2BKT.
Silver metal.
Sold individually.
Mounting and removal instructions can be found here.