The Ultimag 10R is a high grade extremely reliable 10 rounds polymer AR15 magazine - Advantages: - Ergonomic design made for enhanced grip and faster magazine change - Specialty made floor plate for specialty-made coupling options - Dissembled by hand no tools needed - Made of durable light weight polymer composite and steel - Highly reliable construction built to last - Compatibility: 5.56x45 M16/M4/AR15 variants