Endura Flap Thermo Sash 3e Pet Door for Sash Windows - Medium Flap (8" x 15"), Sturdy Aluminum Frame NO TOOLS NEEDED TO FIT : This dog & cat door fits into your sash windows without tools, and takes only a few minutes; for super easy installation and removal. IDEAL FOR RENTERS & HOLIDAY LETS : If you dont want a permanent cat flap but your clients do, the Endura Flap pet door window satisfies both needs; install or remove when needed. STRONG ALUMINIUM NON-TWIST FRAME : Made from heavy duty metal to be long-lasting and robust; comes with adjustable magnet power to help train your pet. AWARD-WINNING ENERGY EFFICIENCY : Endura Flap keeps out the winter cold or the summer heat even in the harshest climates, and keeps those energy bills down. STRONG SECURITY COVER : Includes a sturdy screen cover for when you are away, or your dog is in for the evening; keeps out unwanted doggies or prying eyes.