SPAX 4581820800905 5/16? x 3-1/2" T-Star Washer Head HCR (High Corrosion Resistant) PowerLag Contractor Pax (50 Pieces per Box) Spax PowerLags Screws have a washer head with T-Star Drive and HCR-X (High Corrosion Resistant) exterior coating. Provides a new level of fastening efficiency and reliability to construction. Engineered specifically for demanding wood-to-wood structural applications, PowerLags feature patented thread serrations that eliminate pre-drilling and dramatically increase installation speed - requiring up to 40% less driving torque to increase installation speed. Fastener length stamp on the head provides convenient identification without measuring and aids on-site inspections. HCR-X Coating offers superior X-terior corrosion resistance when installed in treated lumber and is tested in coastal construction environments. All Spax PowerLags are building code listed and load rated, ICC-ES ESR-1782. Features T-Star Washer Head Screw: These T-star Washer Head screws are made of carbon steel and feature High Corrosive resistant (HCR) coating which makes these screws ideal for use in treated lumber and exterior applications Grade 5 Durability: SPAX T-star Screws heat treated to improve strength and reduce breakage. These superior quality screws are great for both interior and exterior applications Patented Thread Technology: Featuring SPAX patented thread technology, these wood screws require no pre-drilling, and drive faster and easier than conventional lags and other structural lag screws. T-Star plus head provides superior bit engagement Built-on Washer Head: The corrosion resistant screws feature low profile built-on washer head design for a contemporary and sleek finish installation and eliminate the need and extra cost of a separate washer Dimensions: 5/16? x 3-1/2? T-star Drive Washer Head HCR PowerLag; Drive Bit Size: T-40. Thread Type: Partial. 50 Pieces Per Box USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.