9mm mag followers

[FlyinBrian]

Just bought a G34 today and it has a #5 follower. My G17 has #3 followers that seem to work much better. I would think that the higher number is an improvement,but in what way? Are #3 followers available or discontinued?

[DannyR]

The #5's function only in the newest tubes. Both #3's and #4's are still available.

[FlyinBrian]

So,can I put the #3 follower in a new mag or is the #5 follower the only one that works in the new mag?