Geberit 111.799.00.3 is a Duofix installation frame designed for wall-hung toilets, specifically engineered for tight spaces. It features the Sigma 8 cm (UP720) Slimlineconcealed cistern, which is significantly thinner than standard models. 
Key Features
Ultra-Slim Design: The cistern is only 8 cm deep, allowing it to fit into narrow wall cavities or slim stud walls where a standard 12 cm unit would not fit.
Frame Height: It has a construction height of 114 cm.
Weight Capacity: Like all Duofix frames, it is strength-tested to bear up to 400 kg(approx. 63 stone).
Water Efficiency: Features a dual-flush system with adjustable volumes. Factory settings are typically 5.8 and 3 liters, but the large flush can be adjusted down to 4.5 liters for improved water savings.
Compatibility: Designed for use with Geberit Sigma flush plates (front actuation only). It supports wall-hung WC pans with a projection of up to 700 mm.
Future-Proofing: Includes a conduit pipe for the water connection of Geberit AquaClean shower toilets and can accommodate electrical connections for touchless flush plates or odor extraction units. 
Installation & Maintenance
Versatile Mounting: Suitable for drywall, part-height, or room-height pre-wall and partition wall installations.
Adjustable Feet: Galvanized feet are infinitely variable in height up to 20 cm and feature non-slip leg supports to simplify leveling during installation.
Tool-Free Servicing: Maintenance and initial installation of the cistern internals can be performed through the service opening without the use of tools. 
Scope of Delivery
The package typically includes:
Water supply connection (R 1/2") with integrated angle stop valve.
Protection box for the service opening.
2 wall anchors and fixing brackets.
WC connection set and 90° PE-HD connection bend.
Fastening material and two threaded M12 rods for toilet mounting. 
Note: The flush plate is not included and must be purchased separately from the Sigma range.