YIIBAII Mini Blinds for 20" W x 64" H Windows 1" Aluminum Horizontal Venetian Blinds Darkening with Rope and Pole can Mounted Inside or Outside

Aluminum blinds measure 19.7"W x 64"H.

Inside mount, fits any window wider than 19.7 inches, best for 20" wide windows; outside mount, most suitable 4" wider than window, like a minimum 15.7"W windows.

So it can be installed on windows from 15.7" to 20".

High Privacy Blinds: Ideal venetian blinds for privacy and light control.

Blackout bilnds control Draw the cord left to lock or right to loose the shutters, Spin the wand to tilt the slats to control sunlight while providing privacy.