Difference in electric brakes

I have 12" brakes. How do I purchase a set of brakes that would improve my stopping power? Is there differences in the magnet size.

This email answer from Dexter;
Mr. xxxxxx,

While the 5.2, 6 & 7K brake3s are all 12x2 in size they do have different lining material, magnets and reinforcement of the metal backing plates.
Thanks

Jim Miller / Dexter Axle ***
You might give Dexter a 1-800 and see if a upgrade in linings/magnets/etc is possible for your axles brakes.
If the trailer is new and the linings aren't broke in yet or not broke in properly the brakes can be wimpy.