• Undercut indented hex washer slotted head Burr-free Full 1/4 in (No 8) head will not strip out of hex driver opening One 1/4 in hex driver accommodates all sizes Undercut - always seats flush Combination lead double thread design Single starting thread machined down to very tip of screw point Instantly penetrates and engages in heavy gauge sheet metal and layered light gauge Consistent hard point Quality controlled heat treat Sharp tapered point will not mushroom or break No walking

Malco's Zip-in® screws are known for their superior quality and is considered by many for being the best screw choice for HVAC metal duct fastening. A unique thread design and quality controlled manufacture spell the Zip-in® sheet metal screw difference. Zip-in's® are made with a sophisticated heat treat process which allows the screw to taper to a fine, sharp point without sacrificing critical point strength. A single starting thread is formed down to the very tip of the point and is the source of Zip-in's® penetrating power. A second thread above the point engages after initial penetration and drills in the screw double fast. Malco's Zip-in® screws are faster driving, with a greater capacity for fastening heavier gauges of sheet metal than any other self-piercing type.