The GROHE Rapid SL 4-in-1 concealed cistern system is designed for wall-mounted toilets and offers optimal sound insulation as well as water efficiency. This complete installation set includes the concealed cistern, mounting frame, control panel, and sound insulation components. The system features GROHE Whisper technology, which prevents sound transmission through ceramic surfaces, making it one of the quietest products in its category. With GROHE EcoJoy dual flush technology, water consumption is reduced by up to 50 percent compared to conventional systems, with the option of a 3-liter partial flush and a 6-liter full flush. The self-supporting steel frame is load-tested for up to 400 kilograms, ensuring reliable stability and safety. Installation is simplified by GROHE QuickFix technology, which allows for tool-free assembly of hoses, inspection shafts, and built-in components. The system adapts to various installation situations with adjustable dimensions: width of 50 centimeters, installation height from 113 to 133 centimeters, depth adjustment from 13.5 to 23 centimeters, and outlet connection for 90 or 110 millimeter diameter. Additional features include SpareFlush technology, which provides 3 liters of extra flushing capacity to eliminate potential clogs in older pipes, EasyConnect system for easy attachment of the control panel and outlet valve, and VarioPort for flexible water connections from multiple directions. The mounting system supports wall thicknesses of 1 to 7 centimeters and includes wall mounting hardware. This concealed installation creates a floating toilet design that makes bathroom cleaning easier while maximizing floor space usage. The complete package includes the Rapid SL WC element, wall mounting set, Skate Cosmopolitan chrome control panel, sound insulation set, and installation instructions.