I have a 58' Vos and I always thought they were BB's but I tore into the guitar yesterday as the neck read 8.38 and the bridge is 7.84. I decided to reverse them but read the tag on the backside and it said 'Custombucker rhythm" and "Custombucker bridge". I never heard of this so I went on line and sure enough that's what was listed. How do these differ? I switched the pu location and am now set, the slightly nasal quality I was experiencing in the bridge went away when moved to the neck and the neck pu sounds great in the bridge...I think the pu's were mislabeled is all.