The three EP001 pickup elements are 20mm in diameter, so as long as the bridge plate has more than 60mm of width, and about 18mm between the bridge pin holes and the sound hole-facing edge of the bridge plate, and there is no bracing crossing the center of the bridge plate, the EP001K should be fine and it should work with most 12-string guitars as well. You can allow for about 2 mm overhang off of the bridge plate with negligible degradation in acoustic transfer. If you're using a classical guitar with a center brace, we recommend the EPS004K with 4 piezo elements.