She will like it
EMR-A was designed to address issues commonly found on existing ambidextrous magazine releases: close proximity of the lever to the bolt catch, obscuring/masking of the the bolt catch's lower paddle, difficult to press lever (on a particular, popular ambi mag release), lever location on the receiver.
From the ground up, it was designed to be more compatible with a factory bolt catch. A new generation bolt catch (like the ABC/R) has angled and/or taller lower paddle makes it easier for it to work with ambi mag catches, but not everyone has or wants to upgrade to a new bolt catch.
EMR-A's lever is low profile for couple of reasons. One is to create as much clearance as possible for bolt catch access, two is a lower profile has less chances of accidental activation.
The lowest profile of the EMR-A lever is immediately below the bolt catch's lower paddle. It is also free of serrations, MCS (Multi-faceted Control Surface) design directs the user's finger to areas where the finger should be. Serrations only exist where the finger should be pressing. The area below the bolt catch's lower paddle is flat and smooth, the user instinctively knows there's nothing there to do.
This is how EMR-A sets its lever apart from the bolt catch's lower paddle. Close proximity of two control surfaces is not ideal, it makes it difficult and more time consuming for users to tell them apart, especially in low light or no light conditions where a visual isn't always possible.
The area marked with red circle shows the the lowest profile, right below the bolt catch's lower paddle.
The serrated length is divided into 80% shallow V, and 20% flat. The shallow V shaped surface fits the finger's natural curve and provides additional surface area, the 20% flat serrations provide added traction and forms a natural index for the finger, this is also part of the MCS (Multi-faceted Control Surface), where a control surface has curves or multiple angles to maximize surface area and ergonomics.
The EMR-A's lever mirrors the location of the right side mag release as much as possible. The feedback from testers and customers have voiced their approval on the placement as natural and intuitive.
Two lengths are available, standard, and extended reach (0.09" longer). Force amplification means a longer lever is easier to press, a mere 0.09" can make a difference. For those with smaller hands or shorter fingers, the extended reach is easier to access and press. For duty and defense ARs and M16s, standard lever should be used. Rainier Arms carries the EMR-A with standard levers.
Prototype EMR-A levers in the white. Production levers are type 3 hard coat anodized in black.
A 10.9lb extra spring rate spring is included. These extra spring rate springs were calibrated and made for the entire Forward Controls EMR family of products (EMR, EMR-C, EMR-A). We've always wanted a stiffer spring for the mag catch, 60% extra spring rate was selected, it provides just the right pressure without unduly and prematurely fatiguing the user's finger.
Here's an EMR-A with extended lever on a PD issued weapon: