This item listing is for a single box of 20rds of IGMAN .223 Remington. This can be used in guns marked 5.56 and 223 Rem. Excellent for AR-15 Rifles and AR-15 Pistols.
(It is, and always will be, safe to shoot .223 Rem. ammunition in a chamber marked for 5.56 NATO.) Source– NRA Shooting Illustrated — https://www.shootingillustrated.com/articles/2018/7/28/556-nato-vs-223-rem-whats-the-difference/
1 box of 20rds