The ProMag AR-15 Roller Follower 5.56mm 5 Round Magazine fits AR-15 5.56mm rifles. The magazine body is constructed of a proprietary DuPont Zytel based polymer and features a patented anti-tilt roller follower. The magazine spring is formed from heat treated chrome silicon wire and is made in the USA.|.3|7.15|3.65|1.6|5-round magazine|Fits AR-15 5.56mm rifles|Magazine body constructed of a proprietary DuPont Zytel based polymer|Patented anti-tilt Roller follower|Magazine spring formed from heat treated chrome silicone wire?|Lifetime Warranty|Made in the USA|T|Warning: This product may contain chemicals known to the state of California to cause cancer and reproductive harm. For more information, visit www.P65Warnings.ca.gov