UNIVENT Automatic Window Opener uses our powerful temperature sensitive hydraulic cylinder that has been in use for decades as the standard in reliability to open cold frames, windows, vents, doors, tunnels, hot houses and demi-lumes. The key features that differentiate UNIVENT is it's compact design, EASY-CLIP-SYSTEM, Double Spring Design, and now our Security Tape for closing the hinge up for winter. The innovative EASY-CLIP-SYSTEM makes it easy to rapidly disconnect one end of the opener without any cumbersome tools, simply undo the clip and have access to the inside of your opening, even in the closed position. The standard cylinder carries a Manufacturer coverage for replacement for 3 years, and replacement cylinders are also easily available to purchase. Material: Aluminum Maximum opening width: 17.5 inches Maximum opening temperature at 86 degrees F Maximum lift: 15 pounds Made in Denmark under the strictest quality standards in the industry. This is a professional and serious home and garden vent opener made by the same company in Denmark since 1978 by Johannes Orbesen and his world famous "Open Sesame" invention.