EASY INSTALLATION: Spring-loaded tension rods hold insert firmly in place within your window frame. CUSTOMIZE YOUR SIZE: Adjustable sizes to fit any window from 23” to 52 ¼”. UNIQUE FLAP DESIGN: UV treated flap with magnets and dense brushing creates a usable yet firm seal. BLOCKING PANEL: Included HDPE blocking panel - nothing goes in or out without your permission. UNIQUE DESIGN: Among the only temporary installation pet door inserts for windows available. The SB Standard Window Cat Door, by Security Boss Manufacturing, offers the best utility pet door for sash windows. Each unit features tempered safety glass and an adjustable spring loaded end for easy install and removal. Each unit comes standard with a security panel that locks into place over the pet door. The SB Standard window frame is made with heavy duty aluminum, that will look great and will last for many years. The sash window pet doors are commonly used for both cats and dogs. The clear flexible vinyl flap is pet friendly, and provides a protective barrier to the outside. The pet opening will be on the right side, from inside looking out. If you prefer a left side pet opening, please contact us at 608-781-7385 or go to www.moorepet.com