The acrylic strike is optional and may be ordered by searching for “Acrylic Strike”. The strike is a clear polycarbonate that presses over the edge of the fixed panel and the door closes against it. Some homeowners prefer this to keep the door from swinging into the shower. The strike also includes a soft acrylic blade that seals against the door and helps prevent water from penetrating the 1/8” gap between the door and the panel. Use is optional and the need for this part varies with the design of the shower. If the shower is small or if the shower spray is directed at the gap between the door and the panel the Acrylic Strike is an appropriate addition to the unit.