Benjamin Marauder Magazine

Just a little tip as your wrench size question means this is your first time assembling a mrod mag.I know they feel and look cheap and they are inexpensive, but they work amazingly well compared to some $2000 air gun mags that have constant problems. Sometimes you don't get what you pay for.

The free play/tension you put on the cover with that flat socket head cap screw is critical as to how well the mag works. Don't over tighten it. Putting a little more spring tension on older mags by moving the spring 1 hole tighter and bending the bottom spring tang a little more to keep it seated usually takes care of all mrod mag problems letting them feed flawlessly...

jmo