ROFU 9420 Narrow Stile Plate, SPDT 1-1/2" Red Mushroom Buttons, 3A/240V

That is what the 9420 is built for. The narrow plate measures 4-3/4 x 1-5/8 x 1/4 inches, which fits the narrow stile of a storefront aluminum door or a narrow mullion face where the standard 4-3/4 x 3 inch plate would overhang. If you have room for the wider plate, the standard size is the other option in the 9400 line.

Two things. Finish: US28 satin aluminum or US40 dark anodized bronze. And switch mode: NO-Momentary, NC-Momentary, NO-Maintained, or NC-Maintained. That is eight combinations in total, so pick the contact state your access control panel expects before you order.

Momentary makes or breaks the circuit only while the mushroom button is pressed, then springs back, which is the normal request-to-exit pulse to a mag lock or electric strike. Maintained latches in the position you push it to and stays there until pressed again, so it is used where you want the door held unlocked, such as a delivery period or an office open hour. Both are offered in normally open and normally closed on the 9420.

Both are push button request-to-exit controls for door release. The ROFU 9420 is a narrow stile plate REX switch with a 1-1/2 inch red mushroom button on a 1/4 inch thick tamper-resistant aluminum cover plate, rated 3A/240V, supplied with two snake eyes security screws and a wrench. The Detex PB-2138-3 is part of the Detex PB-2100 series and is a push button control supplied with a shroud and Form C terminals, so the button is guarded against accidental contact rather than presented as an exposed mushroom head. Choose the 9420 where the mullion or door stile is narrow and a slim 1/4 inch plate is needed; choose the Detex where a shrouded button is preferred.

The ROFU 9420 is built for that application. Its narrow plate measures 4-3/4 inches by 1-5/8 inches by 1/4 inch, so it fits a narrow stile or mullion where the standard 4-3/4 by 3 inch plate will not, and it is offered in US28 satin aluminum or US40 dark anodized bronze to match storefront framing. The Detex PB-2138-3 from the PB-2100 series is a push button control with a shroud, a bulkier assembly better suited to a wall or wide-face mounting than to a narrow mullion.

The 9420 is an SPDT switch rated 3A at 240V, so it will carry a typical low voltage access control or door release circuit directly. It is built from UL Recognized Components. If your run needs more current, the optional 9959 pneumatic time delay is rated 10A at 120 to 240 VAC.

The cover plate is 1/4 inch thick aluminum and tamper resistant, and it ships with two snake eyes security screws plus the wrench to drive them, so it cannot be removed with a common bit. That is the reason it gets used on exit sides in commercial buildings rather than a plastic-housing button.

Order the 9959 pneumatic time delay with the button. It gives an adjustable relocking time of 2 to 60 seconds, rated 10A at 120 to 240 VAC, so the door stays released long enough for someone to get through after the button is pressed. It is an add-on part, not included with the 9420.

Both will give you a changeover contact. The ROFU 9420 is an SPDT switch, so it provides one common with both a normally open and a normally closed path, and it is ordered in NO-Momentary, NC-Momentary, NO-Maintained or NC-Maintained configurations. The Detex PB-2138-3 is supplied with Form C terminals, which is the same single-pole changeover arrangement described in relay terms. Pick based on the plate format and mounting you need at the opening rather than on the contact arrangement.

Two finishes are offered: US28 satin aluminum, which blends with clear anodized storefront framing and most aluminum door hardware, and US40 dark anodized bronze for dark bronze frames. Both come in all four switch modes, so you can standardize one finish across a building and still vary the contact type per opening.

It is a REX switch, meaning a push button that signals the access control system to release the lock. It has no locking mechanism of its own. The 1-1/2 inch red mushroom button gives a large, obvious target for exit use.