Magpul Maglink Coupler - 30/40 RD PMAG 

• Made in the USA
• Durable, Lightweight Polymer Construction
• Two Piece Design
• Keeps Additional Ammo Accessible on the Weapon
• Allows the User to Attach Two Magazines Together
• Increases Efficiency with Speed Reloading
• Compatible with 30/40 Round PMAG AR/M4