10 Pieces - 41mm Piezo Disc Elements with 4" Leads, Jumbo Contact Pickup CBG Cigar Box Guitar DIY Great for CBG / Acoustic Instrument Pickups, Stomp Boxes, Contact Mics, Etc... 41mm brass outer diameter plate, 100mm leads Resonant Frequency: 1.0KHz +/- 0.3KHz Capacitance @ 120Hz: 70,000pF +/- 30%