The CRL Jackson® 21111 Series ANSI Grade 1 Overhead Concealed Closer with "S" Side-Load Hardware Package consists of a Closer mechanism, which depending on the selected spring size and function, is suitable for a range of doors from 30" to 48" (762 mm to 1.22 m) wide. This closer comes standard with an adjustable hydraulic backcheck feature that provides the ultimate protection from wind or violent door swings to prevent damage to the closer and opening without impeding normal traffic flow. The Closer is packaged complete with Cat. No. 20219 Mounting Clips, 20400B Side-Load Arm, Type "G" 20902 Bottom Pivot Set for floor mounting, and complete installation instructions. The Closer has dual independent valves for closing operation (one valve for closing, one valve for latching). 90º and 105º, Hold Open and No Hold Open models are available. Closers fit into standard 1-3/4" x 4" (or larger) header extrusions.