Lead weights/tape

I noticed multiple tour players have affixed tungsten/lead weights to some of their clubs. I was just curious as to why this is? Obviously for additional weight but why the specific placements of certain weights on certain clubs? Thanks - CB  

C.Briggs

I noticed multiple tour players have affixed tungsten/lead weights to some of their clubs. I was just curious as to why this is? Obviously for additional weight but why the specific placements of certain weights on certain clubs? Thanks - CB  

Placement of lead weight affects ball flight.  Closer to the heel promotes a draw and closer to the toe promotes a fade.   Closer to the sole is a higher ball flight and closer to the top of the blade is for a lower ball flight.  If they grind down the sole, they have to add weight to compensate.   2 grams of weight in the head = 1 swingweight point of difference.