Coarse threads with type 17 point Quik Guard proprietary double barrier corrosion protection Nibs under head for countersinking Used in Quik Drive Tools PRO250, PRO300S, 2000 SDS. Free Bit in every box of screws #2 Undersized square drive BIT2SU Quik Drive DTHQ212S Trim Head Screw for Deck and Dock 2 1/2-inch with Quik Guard Corrosion Protection. Collated sharp point screw in wire size #8 with type 17 point and nibs under the head for easier countersinking in composite decking. Trim head with #2 undersized square drive head. (uses BIT2SU bit). Used in Quik Drive Tools; PRO250, PRO300S, 2000SDS. 1500 screws per box. QuikDrive DTHQ212S #8 x 2-1/2" Trim Head Deck Screw (1500) #8 Deck/Dock Wood / Composite Decking-to-WoodFeatures: * #2 Undersized square drive - BIT2SU * Coarse threads * Nibs under the head for easier countersinking * Type 17 point * Trim head * Quik Guard coating * Curved collation