Since 1994 cooperation with professional designers has led to trend-setting designs. The Opal model, designed by Jochen Flacke in 1994, represented a rejuvenation of the very traditional classic designs of his time.

In 1998 Sabine Bischof designed the Indura model. She used stainless steel as a material in the design of entrance doors for the first time. In 2003 Detlef Rahe continued the minimisation of stylistic elements with the Penda model. He emphasised vertical lines with the aim of unobtrusively integrating the entrance door into the overall architecture of the house facade. In 2007 horizontal lines were emphasised in the Metris model. For the first time delicate, elegant, square stainless steel inlays were used. The design by Sabine Bischof was awarded the Dr. Hahn design prize in that same year.

Sabine Bischof's Alliso model also followed the architectural trend of placing more emphasis on horizontal lines. On the market since fall 2010, it is enjoying steadily increasing resonance with the public. Then in 2013 Ms. Bischof perfectly conveyed the design approach for multi-piece structural forms with the Talio model.

We place a great deal of importance on the symbiosis between form and function. This characterises our cooperation with the designers Sabine Bischof, Nina Wolf, Detlef Rahe and Kressel + Schelle.