A limiting automatic opening system with Cremonese and fully automatic release through the operation of the handle. The Jeko is an innovative solution by Esinplast for those who want to have an internal opening system for windows with one or two sash; this limiter has been designed to facilitate the gradual recirculation of air allowing ventilation with opening the door (microventilation). The system was born as an alternative to the flap door; compared to the latter, the Jeko has a greater ease of installation and a lower cost.Can be used on fixtures of any weight. Closed system is not visible.