This is the Savage 10 round .17HMR & .22WMR magazine in blued steel for the Savage 93 & 90 series of rifles (#90010).
For Savage rifles with serial numbers 1158378 and higher, it will not fit earlier models.
Manufactured at the Savage factory in Lakeland, Ontario this magazine also fits the Savage and Lakefield 502 and 503 rifles.