These heavy-duty staples are designed for safe and secure insulation of NM (Romex®) cable gauges 14/2, 14/2G, 12/2, 12/2G, 10/2, and 10/2G, and other wire up to 31/64-Inch (12 mm) in width. For exclusive use with Klein's Loose Cable Staplers (Cat. Nos. 450-01 and 450-100). These UL listed insulated staples are available in packs of 300.