The 4-Point Studded Knobs by POWERTEC. INCLUDES: Black 4-Arm Knobs with 1/4 in.-20 Threaded Studs (5-Pack) These multi-functional 4-arm knobs provide you with reliable fastening action for an assortment of general purpose clamping projects. They not only give you increased torque, but simply mount these knobs into a 1/4 in.-20 threaded hole and they'll give you optimal control and gripping action to secure your applications. The user friendly build allows you to utilize a secure hand-grip to position, tighten and hold your equipment, jigs, fixtures and machinery. These will also eliminate the need to purchase separate heads and studs that ultimately pull out. Premium Construction and Design The black knob is made with high quality, durable polymer plastic and flaunts an easy to grip design that comes with ample finger gripping space and is comfortable to twist and secure with the hand. The 1/4 in.-20 in. threaded stud is 2 in. L and features a high precision steel construction with a zinc plated coating to help prevent corrosion or wear and tear. Material: Brass.