Stainless Steel Protector Sleeves are to be used on wood or composite posts to help prevent cable from wearing into the post. The sleeves are highly recommended to be used in post holes whenever the cable enters or exits a post on an angle (typically on corners). The sleeves will help your cable railing maintain proper tension over time. A second great use for the Protector Sleeves is purely aesthetic. Sometimes, when drilling holes in posts for the cables, wood tends to splinter off, leaving less than perfect holes. The sleeves have a 1/2" silver flange on them which covers any rough edges of the drill holes. PROTECTOR SLEEVE SPECIFICS: Overall Length = 3/4" Flange Diameter = 1/2” Required Hole Diameter = 1/4" (to be tapped in) Cable Sizes = 1/8”, 5/32” or 3/16” Have a hassle-free cable railing installation by using VistaView branded materials, tools and wealth of online resources and customer support (phone and email, before and after the sale).