Metallics FST100SS 1-1/4 x 9/16 Cbl Stpl 302-SS

The FST100SS is a 1-1/4 by 9/16 inch cable staple, so the 9/16 inch opening under the crown is what sets the cable it will straddle. Measure the flat width of the cable or the outside diameter of the bundle you are securing; anything wider than 9/16 inch will not seat under the crown, and the 1-1/4 inch leg length is what gives you penetration into a stud or joist.

It is made from 302 stainless steel, which is the corrosion resistant grade electricians reach for on exterior runs, marine work, coastal installs, and damp or washdown areas where a plain or galvanized staple would rust and bleed. For dry interior rough-in you can use it too, it is simply more material than most indoor branch circuit work calls for.

The FST100SS is an all metal 302 stainless staple, 1-1/4 by 9/16 inch, with no plastic saddle. Insulated staples put a plastic bridge across the cable to spread the clamping load and cushion the jacket, which is why many electricians prefer them for NM cable in a finished wall. A bare metal staple like this one is the choice when corrosion resistance matters more than cushioning, for example outdoor or marine fastening, and it also holds up where UV or heat would degrade a plastic saddle. Drive it so the crown just contacts the cable rather than crushing it.

Yes, 1-1/4 inch is the usual leg length for hand driving a cable staple into dimensional lumber such as studs, joists, and plates. It gives enough bite in wood while staying short of the 1-1/4 inch depth where nail plate protection becomes a concern on a 2x framing member. It is a wood fastener, not a masonry one, so for concrete or block you need a different anchoring method.

Order it as Metallics FST100SS. That is the full part number for the 1-1/4 by 9/16 inch 302 stainless cable staple, and the SS suffix is what separates it from the plain steel and galvanized versions in the same staple line.