- This 500-pack of 9/16 inch Romex metal staples is a must-have for anyone in the electrical industry. These staples are made of high-quality metal and are perfect for securing your electrical wires. The staples can be fastened using a hammer and are designed to hold the wires firmly in place. The staples come in a metallic finish and have a unit type of "unit". They are 5.375 inches in height and 3.375 inches in depth. These staples are not certified or listed but have a 90-day return policy. They are ideal for use in staple guns and can accommodate staple width of 0.5625 inches. These staples are a great addition to your toolkit!