Metallics JTA516212 Anchors 5/16 X 2-1/2 Hllw Block T-Anc (Jar 25)

The Metallics JTA516212 is a 5/16 x 2-1/2 inch hollow block toggle anchor, packed 25 to a jar.

Hollow block is exactly what the Metallics JTA516212 is made for. It is a toggle-type anchor, so the wings pass through the face shell of the block and spread out inside the void, bearing against the back of the shell rather than relying on friction in the hole. A sleeve or wedge anchor needs solid material to expand against and tends to crush out the thin face shell of a hollow CMU. If you are anchoring into solid concrete or the solid web of a block, use an expansion-type anchor instead.

On the JTA516212 the 5/16 is the bolt diameter and the 2-1/2 inches is the bolt length, so the usable grip is 2-1/2 inches minus the face shell thickness it passes through and the thickness of the item you are fastening. On a standard block face shell, that leaves enough for a strut channel, a panel bracket, or a conduit clamp. If you are stacking thick backing plates, step up to a longer bolt length in the same 5/16 family.

Yes, and this is where most installers go wrong. A 5/16 toggle anchor needs a hole big enough for the folded wings to pass through, which is substantially larger than the 5/16 bolt itself, not a 5/16 hole. Check the hole size marked on the Metallics jar label before you drill, and remember the anchor is not retrievable once the wings drop inside the block void.

Yes. Metallics catalogs the JTA516212 as an electrical fastener, and a 5/16 toggle in hollow block is the usual way electricians hang strut channel, conduit straps, junction boxes, and panel brackets on CMU interior walls without coring into the solid web.

The jar of 25 suits an MRO shelf or a service van where you are setting a few anchors at a time rather than a full install. One part number, one size (5/16 x 2-1/2), so there is nothing to sort on the truck. Crews doing a whole building of strut runs usually standardize on one diameter and carry multiple lengths instead.