Like B3 says, there are lots of different blade types out there...........some are mild steel others actually magnets.They all do the same job and aim the magnetism up towards the strings and the argument for them is that, as on continuous pole, you don't get any drop out.I must admit I think I smell b/s on that one, I've never heard dropout from string to string, no matter how hard I bend, on standard 6 pole pickups.The tone of a blade is very focused and ,IMHO, not suited to vintage applications but as several of you have pointed out, they have their fans.The 'real' XL500 is a good unit, don't be put off by the fake Korean ones, they sound weak and are very unreliable.