Arsenal original Bulgarian factory production, Left-side metal folding Mil-Spec buttstock. The Buttstock metal is with straight edge and ribbed plate. This Left-side folding triangular metal stock incorporates a slick hinge mechanism for a solid lock-up. A direct replacement for the solid polymer folder that is standard equipment on the Arsenal SLR Series rifles, and uses the same standard 4.5mm pin (sold separately). It also has the same pivot pin angle as used on the SLR Series rifles. Note: The rear trunnion with folding stock hardware is sold separately.