1) Turn your mag botttom up.
2) In the middle of the bottom you will see a hole with a bump coming up through it.
3) With a small screwdriver or something similar push the bump down into the hole about 1/16 ".
At the same time, slide the mag bottom toward the front of the mag.
Be careful - once the bottom slips off the mag, the spring and inside bottom piece can fly out!
4) While holding the spring and inside bottom piece in the mag well, slide the Bersa bottom on the same way the old bottom came off.
That's it! ;D
I have them on all my mags - makes a big difference for me.
OOPs sorry, TxCajun posted his as I was composing mine. :-[