For eBay, this is not a "magazine extension and does not violate your policies"
This is a very simple drop in replacement. Replace your existing follower with this. No permanent modifications are necessary.
Simply remove the magazine baseplate & the spring and the original follower. Then remove the follower button that holds the follower in the magazine. Replace with the new follower, re-insert follower button and reassemble the magazine.
Same function as Tandemkross Maximus Plus 1 but much cheaper.
New updated design as of 4/20
SALE IS FOR A PACK OF 12