There are two types of magnetic brake designs. The old standard works with magnets and a (steel flat disk) attached to the aluminum spool. this is a "constant brake", the magnets pull on the disk throughout the entire cast (It's pull is the same at slow or fast speed but speed overcomes the pull). The other method works on the physics principle called the "eddy effect", where a "non ferrous" (aluminum) spool (while spinning) breaks that magnetic field which in turn acts as a brake. The advantage here is that the "eddy effect" is strongest at fast speed. As your lure slows down, the effect becomes less and less. Meaning, you get the brake when you need it (to prevent a birds nest). The cast can go further because breaking is reduced as the lure slows down. You get the opposite reaction on a "constant brake" which works best at slow speed and less at high speed, so you have to tweak in a higher brake setting to avoid a bird nest. Anyhow, that's how I understand it. Something I had to ask about when I purchased a KastKing baitcaster reel.
