The Andersen 400 Series tilt wash double hung window was first introduced in 1992 and is still made today. This window has compression fit jamb liners that keep the jamb liners tight against the sash. This window tilts inward for easy cleaning. To tilt the lower sash in you need to raise up the lower sash several inches then slide the "wash assist" into place. The wash assist is a piece of vinyl that slides in the window track. It slides down the track and is pushed between the sash and the jamb liner. The easiest way to identify this window is to look for the Wash Assists that will be clearly visible in the track.