Simpson #9 x 1-1/4" Collated Cement Board Screw, High-Low Thread, C-3 Galvanized 1500PkModel No. CB3BLGHL114S Coating Material Mechanically Galvanized, C 3 Screw Size #9 Length (in.) 1 1 4 Drive Type #3 Square, Undersized Head Type Ribbed Wafer Head Thread Type High Low Threads Point Type Sharp Point Compatible Tools Quik Drive PROLDHG2 Packaging Qty. 1500 The CB3BLGHL is designed for cement board to wood applications (for coarse, porous, and softer materials). This collated screw is used with the Quik Drive PROLDHG2 underlayment