Precision MB822-689/695 Bottom Fitting For 822 Mullion - Aluminum

The Precision MB822 is the bottom fitting, or mullion base plate, for the Precision 822 removable mullion, in an aluminum finish. This is the part that anchors the bottom of the upright to the floor and locks it solidly into the door opening. A removable mullion stands in the center of a pair of doors to give a rim exit device something to latch against, and the MB822 is what holds the bottom end in place. It's investment cast steel, 2 inches wide by 3-1/2 inches deep, and ships with steel anchors made for fastening into concrete floors.

What the bottom fitting does in the assembly

A removable mullion is a two-anchor system. The top locks into a cap (the MC822) mounted in the frame header, and the bottom seats into the base, this MB822, anchored to the floor. Together, the cap and base hold the upright rigid so it can take the strain of an exit device latching and people pushing through. The MB822 specifically handles the floor end: its investment cast steel body resists the lateral load, and the included steel anchors secure it into a concrete slab so the assembly doesn't shift or work loose over time.

This base fits the 822, which is the standard 2 inch by 3 inch removable mullion in the Precision lineup. There's a separate fitting, the MB811, for the smaller 2 inch by 2 inch 811 size, so matching the base to your upright is the first thing to get right.

Precision MB822 specifications

• Type: Mullion base plate (bottom fitting) for the Precision 822 removable mullion.

• Material: Investment cast steel.

• Dimensions: 2 inches wide by 3-1/2 inches deep.

• Anchoring: Furnished with steel anchors for concrete floors.

• Compatibility: For the Precision 822 (2 inch by 3 inch) size. Pairs with the MC822 cap at the top.

• Finish: Aluminum (689), with dark bronze (695) available.

• Function: Secures the bottom of the upright into the door opening for rim exit device applications.

Why the right base matters

A removable mullion is only as solid as its two anchor points. If the fitting is wrong for the size or poorly anchored, the whole upright flexes, which means the exit device may not latch reliably and the assembly loosens with use. The MB822's investment cast steel construction and concrete-floor anchors are built to keep the 822 rigid for the life of the opening. For anyone servicing or specifying a Precision rim exit device on a pair of doors, getting the matching base is what makes the upright actually removable and reliable, you pull it when you need a clear opening for moving large items through, then drop it back in and it locks down solid.

Two things to confirm before ordering: this fitting is for the 822 (2 inch by 3 inch) size, not the smaller 811, and it's designed to anchor into a concrete floor. If your installation differs, confirm the part matches your upright and floor type first.

Order the Precision MB822 from American Locksets

We stock the full Precision line from authorized distribution, so every fitting ships with a real manufacturer warranty. Find the matching 822 upright, MC822 cap, and other components in the Precision mullions category, or browse all exit hardware.