Pieces that are components of a frame for a window having a threat side and a safe side include a base and a pressure plate that together form part of one of a sill section, a head section, and a jamb section of the window. The base and pressure plate are elongated in a longitudinal direction. The base has (1) an L-shaped cross-section at a near portion of the base to receive an end of a glazing unit from the threat side of the window, and (2) a first pocket formed in a far portion of the base and running in said longitudinal direction. The rear portion is closer to the threat side than the far portion. The pressure plate is to be assembled with the base so as to secure the glazing unit in the corner. Other embodiments are also described and claimed.