The Hillman Group 270021 Flat Zinc Washers, 9/16-Inch Product Description Used in applications with nuts and bolts. The flat washer provides a greater bearing surface which helps prevent a nut or bolt head from tearing through the material. Flat washers are commonly used in decks and fence building. The called out size is the inner diameter of the washer. From the Manufacturer Used in applications with nuts and bolts. The flat washer provides a greater bearing surface which helps prevent a nut or bolt head from tearing through the material. Flat washers are commonly used in decks and fence building. The called out size is the inner diameter of the washer. Features Flat Washers Are Ideal For Increasing The Load Bearing Surface Under A Fastener's Head By Distributing The Load Through The Washer These Washers Help To Prevent Bolts Or Nuts From Pulling Through A Surface Zinc Plated From The Brand Name: The Hillman Group 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.