Abstract: A conventional frame for a jalousie type window is made secure against passage therethrough by individuals by inserting bars through the openings in the side frame members normally utilized by the jalousie support brackets which are then pivoted on the bars. The ends of the bars where they project through the side frames members of the jalousie frame are rigidly connected as by welding to a respective one of a pair of bars parallel to the outer side of the side frame members. The bar ends extend beyond the second bars for embedment in a masonry surrounding a window opening adapted to receive the frame. The brackets and jalousie slats are controlled in a conventional manner.