Balls are best! Ernie Ball Ukulele strings are made from 100% nylon monofilament. Ukulele strings are offered in traditional clear resin for a bright, balanced tone with excellent projection and black resin for a warm, rich tone with percussive attack. Ernie Ball Ukulele strings feature ball end construction for easy installation and enhanced tuning stability. Gauges .028, .032, .040, .028. For concert or soprano. • MFSKU P02329 • UPC 749699102755