This magazine has been discontinued by Anschutz.
This is the extended 5 round .223 Remington factory magazine for the Anschutz 1770 series rifles (1770-U3 010310).
Made from steel and a tough polymer this single stack magazine is also strippable for cleaning.
You can’t go wrong with having extra magazines, whether it’s for quick loading times at the range or in the field. Or, as a backup in case you lose one or drop one in the mud.