The Reverse Retrofit version attaches to the window frame and restricts the sash opening by operating on the top of the bottom sash. The units are single action, so fitting one either side of the window frame ensures compliance with ASTM F2090 2008 and 2010.

These units have been Focus group tested and have been proven to be operable without prior knowledge or tools. Various forms of the Reverse Retrofit are available. Selection is dependent upon the distance of the Frame from the Sash. Please see drawing above for further information. Simply Measure this distance and choose the model from the table below.

This type of Angel Ventlock can be Factory Fitted or used as an Aftermarket Device. Particularly useful on Vinyl and single hung windows where there is insufficient room on the top sash to install any of the versions listed.