Rockwood 321 Latch Protector, 1-1/2" by 10", Mortise Lock Type

It mounts with 5/16-18 carriage bolts and hex drive sex nuts. The bolts go through the door and thread into the sex nuts from the inside, so there's no exposed screw head on the outside for someone to back out. You drill through the door for them, which is what makes the guard hold when the door gets pried.

No. A latch protector like the 321 only does anything on a door that swings away from you, where the latch edge and the gap are reachable from the attack side. On an in-swing opening the stop covers the latch and a guard buys you nothing. Every latch guard in this class, including the Don-Jo GLP-307 and LP-307, is specified out swing.

The 321 is .105 inch material, available in steel and stainless steel, with the stock we carry in stainless. Stainless is what you want on an exterior opening or anywhere it gets washed down, since a painted steel guard will rust at the bolt holes first.

One finish: 630, satin stainless steel, which is the US32D equivalent. That's the standard commercial finish on most institutional exit devices, push plates and mortise trim, so it matches out of the box on a typical school, hospital or office opening. If your building is standardized on satin chrome US26D, the 630 reads very close but is not identical.

For a mortise-locked hollow metal door, the closest alternatives are guard plates from the Trimco PG8000 Series, which covers both panic and latch guards. On the Don-Jo side the LP-307 and GLP-307 are built for aluminum entrances rather than mortise-locked steel doors, so they solve a different opening. The difference that matters is the pattern length and where the bolt holes land relative to your lock face.

You can retrofit it in the field. Mounting is 5/16-18 carriage bolts with hex drive sex nuts, so the work is drilling through-holes in the door leaf at the guard's hole pattern and pulling the bolts up from the inside. No mortise, no cutting into the lock prep, and the existing mortise lock stays where it is.

The Rockwood 321 is stainless steel, supplied in 630 satin stainless steel, and is a commercial product. The Don-Jo GLP-307 is an entrance function latch protector for aluminum entrance doors at 2-5/8 by 7 inches, out swing. If the drawing calls for a stainless steel plate on a mortise lock opening, the 321 is the one that matches that material and lock type.

Yes, that's the intended use. Rockwood hardware is specified on institutional buildings, offices, retail, educational, detention, sports facilities, hotels and restaurants. The 321 is a commercial-grade part in .105 stainless with through-bolt mounting, which is what holds up on a high-traffic exterior opening where a surface-screwed guard gets defeated.