FastenMaster FMTR2-003-350TSFP 3-Inch TrapEase II High Density Composite Screw for TREX Transcends, Fire Pit, 350-Pack Oversized top thread traps most loose composite material during installation Concave underside of head conceals material for clean appearance Guaranteed corrosion resistant coating in pressure treated lumber. ACQ approved Bottom thread and point are designed for maximum pull-down power Deep #1 square drive provides the best bit engagement, reducing cam-out