Gliding / Sliding Windows

As a two-sash window, either one sash operates by sliding on a track (XO or OX, with left or right sash as the operable sash, respectively, as viewed from the house exterior) or both do (XX). In a three sash design, a fixed picture window sits in the middle, and the ends slide in towards the middle to open (XOX). Known as a double-end slider or glide picture window, the ratio of sash widths is typically 1:2:1, or 1:1:1. The insect screen is on the exterior.