The afternoon seminar was part of an original statement of the Cheh plast employees who had visited exhibitions, conferences and seminars within the country and abroad. With photos and promotional material from the largest specialized exhibition of windows and doors - Fensterbau Frontale 2012. Eng. Iskren Neshev and Mr. Yoto Yotov introduced us in the innovations and the atmosphere of the exhibition. Their trip was organized by REHAU Bulgaria Ltd. The gentlemen introduced the system of forced ventilation recovery systems built into the frame of the window, and then they had "walked us among" the stands they were impressed on.