Other interior shutters use stationary louvers that do not rotate (fixed louvers); solid raised or flat panels; fabric inserts; or tinted glass. Shutters can be configured in a single tier unit that has one shutter top to bottom of a window opening as well as multiple tiers. Multiple tier units feature separate shutters on each tier which allows the top shutters to be opened independently from the bottom shutters. Café-type shutters refer to shutters that only cover the lower portion of a window.