Astro 7409 9-Piece 3/8-Inch Dr. Twist Socket Damaged Fastener Removal Set Spiral and tapered internal splines are designed to grip the perimeter of any damaged or rusted nut, stud, pipe nipple or bolt Place the Twist Socket on and twist the damaged fastener off Safe and fast removal of damaged fasteners and easy removal of the fastener from the twist socket Made of top quality CrMO steel provides good wear resistance and durability Kit includes: 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 19mm sockets