1-String Pickup for Bass on a Fender Jaguar (Jaguarillo) - YouTube
Single Coil Sized 4 String Bass Pickup Cigar Box Guitar Pickup - Guitar Parts & Accessories - AliExpress
Amazon.com: Ktaxon 4 String Electric Bass Guitar, 36-inch Bass Guitar Kit with Split single-coil Pickup, Rosewood Fretboard, Mahogany Body for Kids, Boy and Girl(Red) : Musical Instruments
Synco single string pickups - anyone tried these yet? | TalkBass.com
Big Single 6 - Nordstrand Audio
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