This Single Mortise Lock Thumbturn by Prime-Line Products is constructed of heavy-duty cast zamak and comes in a soft, aluminum finish. The thumbturn cylinder measures 1-inch in length and features a standard thread of 1-5/32 inch x 32-inch. This item includes one thumbturn with one 1/4 inch thick trim ring. It is used on commercial aluminum and steel doors equipped with commercial deadbolt lock mechanisms, constructed by many commercial door manufacturers. The Tee-shaped thumbturn is easy to turn, and it features a Schlage keyway. Older model thumb turns can become difficult to turn, due to the accumulation of dust and/or possible corrosion, but these Prime-Line single mortise lock thumbturns are easy to install.