Easy to open plastic clasp secures elastic material in place, and allows the user to easily adjust the wrist band size. 4 mm Stud, to fit 4 mm spring loaded medical snap socket. Non-allergenic stainless steel base plate, provides excellent skin contact, for superior grounding. Insulating cap, thermoplastic. Metallized, high flex tinsel, black jacket. Reusable. - Desco Wrist Strap Kit, Closure Type: Clasp, Cord Type: Coiled, Size Group: Universal, Snap Size: 4 mm Stud, Cord Length: 6 ft, Material: Elastic Fabric, Color: Red, Number of Conductors: 1, Resistance: 1 megohm.