The unbranded copies from EME ,and others, have the magnets fixed with clips and a better adhesive.
Quality is better than OEM, the only thing that is cheap is the price.
EME has good quality heavy duty battery cables too, at less than half the price some folk are charging.
There are cheaper Ebay sources than EME, but EME stands by his stuff, and has a no quibble replacement policy, which most Ebay sellers wont have.