JP Enterprises VMOS Bolt Carrier Heavy Version Black. Made from stainless steel with a striking black finish this heavy-duty bolt carrier group can help eliminate any cycling problems you might have in your rifle. It is tested rigorously to ensure high-quality performance and the Variable Mass Operation System (VMOS) allows for custom tuning to get the perfect specs for your gas settings to prevent malfunctions and fouling. This is the heavy version which comes with one steel two tungsten weights which you can exchange for lighter steel weights to modify the rifle's capabilities. If you're looking for a solid upgrade to your favorite AR10 pick up the JP Enterprises VMOS AR BCG today. Specifications for JP Enterprises VMOS AR Bolt Carrier: Manufacturer: JP Enterprises Color: Black Condition: New Features of JP Enterprises VMOS AR Bolt Carrier Enhanced tunability of operating system Guaranteed reliability of difficult configurations Overcomes all fouling build-up Roller-burnished bore for frictionless operation Rock-hard QPQ finish provides remarkable natural lubricity Extremely smooth cycling with proper lubrication Increased bearing surfaces for slower wear and longer component life Longer cocking pad for optimal reliability Additional forward assist serrations for one full inch of travel Made in specialized factories Package Contents: JP Enterprises VMOS AR Bolt Carrier JP Enterprises JPBC-7H2: VMOS Bolt Carrier Heavy Version Black