These Are Genuine Duracell Brand Aa Alkaline Batteries They Are Packaged In A 4 Battery Unit. You Can Use These Batteries As You Would Any Batteries, In Toys, Smoke Alarms, Corldless Microphones, Etc. The Only Difference Is, These Batteries Will Last Longer Than The Others You Have Been Using.. You'll Want To Switch To Duracell From Now On, For All Your Battery Needs. Genuine Duracell Brand Size: Aa Alkaline 4 In A Package Blister Packed Long Lasting And Reliable