Affordable, durable vinyl window with an operational bottom sash. Low-E 366 glass with argon provides more protection against heat gain by blocking harmful infrared rays, as well as providing greater energy savings. Top sash is stationary; bottom sash slides open vertically. Built with high-quality extruded vinyl (in your choice of white, desert sand or almond) that won't chip or peel and resists fading, mildew and condensation. Block and tackle balance system supports the vertical operation of the sash in single-hung and double-hung styles, so the sash will not slam shut. Weatherstripping creates a tight seal against outdoor elements. Optional tilt assist feature lets you tilt the sash in for convenient cleaning from inside your home. Integral nailing fin surrounds the perimeter of the frame and helps make installations weather tight; for new construction or replacement.