Transparency for more zest for life
The KELLER 4+ premium design sliding system underlines the clear line of modern architecture and fulfils any wishes for living areas that are generously flooded with light.

Keller Minimal Windows®4+ is a virtually frameless sliding system with universally insulated aluminium profiles into which very large panes of glass are set. The peripheral frame profiles can be fully installed into the wall and ceiling and also into the floor for barrier-free access.

Functionality adds to the quality of life
The extreme ease of movement of the optimised stainless steel roller/rail system enables the comfortable, manual movement of large glass areas.  

The high-performance carriages - a decisive design detail - guarantee high operational reliability and durability.  On request, concealed electric drives and locks can be used to increase operating comfort according to the individual system configuration. 

Resources and energy efficiency
The highly-insulated premium series meets the high standard of energy-saving glazing and maximum energy efficiency. It offers outstanding thermal insulation thanks to the use of triple glazing with a maximum glass thickness of up to 56mm and can be used in low-energy and passive housing.

Performance
The system offers all conceivable sliding variants extending up to 3-track systems and corner-post-free internal and external corners. The sliding leaves can be manufactured up to a height of 4.5 m and with a leaf area of up to 12m² (fix leaves up to 18m²).  Leaf weights of up to 1000kg can be used.  This is made possible in particular by the specially developed carriage technology, while retaining the slender profile design.

 A unique feature is that several leaves with a total weight of up to 2000kg can be silently moved by just one electric drive.