Fishman recommends removing no more than 5/32″ of material when fitting either of these bridges to your instrument. There are two reasons for this: The string volume may be uneven and unpredictable if the strings end up too close to the embedded pickup element. Secondly, removing too much material can weaken the upper part of the bridge, and may cause structural damage when under proper string tension. As always, we recommend professional installation for these products whenever possible.