Forward Controls Design Milspec Through Hole Enhanced Magazine Release Button Serrated Black EMR-H Serrated. The form fitting curve along with horizontal serrations create a self centering surface that inhibits the finger's vertical movements. The EMR-H has a milspec through hole for the magazine catch's shaft and is only 0.02in taller than the factory magazine release button. When installed the EMR-H has minimal protrusion above the mag release button fence on most forged receivers. Specifications for Forward Controls Design Milspec Through Hole Enhanced Magazine Release Button: Manufacturer: Forward Controls Design Color: Black Fabric/Material: 4140 Steel Package Contents: Forward Controls Design Milspec Through Hole Enhanced Magazine Release Button Forward Controls Design EMR-H Serrated: Milspec Through Hole Enhanced Magazine Release Button Serrated Black