EMR-A is a long in development ambidextrous magazine release for .223  AR receivers.  Original concept and design was complete in 2015.  After numerous changes to the mag catch geometry and lever shapes,  final design was made into working prototypes in 2017, and first shown in public at Cola Warrior West III. EMR-A is an ergonomic ambidextrous magazine release.  The placement of its lever is well thought out to closely mirror the magazine release button on the right side.  The portion immediately below the bolt catch's lower paddle has a lower profile to avoid interference, heretofore a common drawback of popular ambidextrous mag catches, it is also left smooth.  The serrated length of the lever is split into a shallow V shaped serrations (80%) that conform to the curvature of the user's finger, and straight serrations (20%) that form a natural index point, and provide additional traction.  They refer to the design as Multi-faceted Control Surface, the difference MCS makes has to be felt to be fully appreciated.

A 10.9 lbs. rated magazine catch spring is included with each EMR-A. They've long considered the standard magazine catch spring to be rather weak (rated at 8.3lb), accidental / unintended mag drops can take place if a user slings his weapon, and has gear and pouches on the vest.  A stiffer mag catch spring mitigates these risks, thus it is an integral part in the EMR-A package.

EMR-A's catch is made from CNC machined 4140 steel and black nitride coated, its lever is 7075 aluminum and Type 3 hard coat anodized.  The roll pin has a shear strength of 800lbs.

Incompatibilities:

• Due to lack of standards for 308 ARs, EMR-A will not work with all 308 AR style lowers.
• Geissele's Maritime Bolt Catch.  Material from either the top edge of EMR-A's lever, or the bottom edge of Maritime Bolt Catch's lower paddle may need to be removed for both to work together.  The close proximity of these two control surfaces makes this combination less than ideal.
• CMC's anti walk pins
• KNS Gen 2 anti-rotation trigger/hammer pins.  KNS Gen2 Mod2 and Gen JJ, and Gen ST (Spikes Tactical) are compatible with EMR-A with standard lever, but not with extended lever. Gen2 Mod2's pins connecting bar may require minor fitting on thicker receivers to create adequate clearance for the EMR-A's lever when pressed.
• HK 7.62mm AR style rifles, MR762 series.
• Aero 308 AR lower receivers.
• Hodge Defense Mod 2  lower receivers.
• APF side folder lowers
• 17 Design billet lowers
• Uintah Precision lowers
• Silencer Co SU 4766 lowers Battery assist device levers.
• Receivers with the left side fence around the bolt catch and mag catch, such as some CMT, Magpul and AR15.com billet receivers.  EMR-A requires the left side of the receiver to more or less adhere to TDP specs.
• May not be compatible with Seekins SP223 and AR10 B receivers.

Please NOTE:

• EMR-A's lever pivots on the receiver.
• EMR-A needs to be removed before installing / removing the trigger.  EMR-A is installed and removed in the same manner as a factory mag catch.
• Please wear eye protection while installing EMR, EMR-C, and EMR-A with the 10.9lb mag catch spring, there's considerable spring tension in the 10.9lb spring.
• Do not use anti-rotation pins, most of them do more harm than good, they're also mostly incompatible with EMR-A.  A properly designed trigger doesn't need them. 
• Due to the lack of standards for 308 ARs, with every manufacture specs differing from another, they do not recommend EMR-A for 308 ARs.
• EMR-A was designed for TDP spec forged lower receivers, if your lower is billet with thick walls, or differ a great deal from TDP specs.