Stranded Steel/Nickel wound. 
Helicore strings are a multi-stranded steel core string, offering a warm tonal quality with excellent bow response. They are easy to play and are suitable for all double bassists. 

Features: 

• Multi-stranded steel core strings. 
• Warm tonal quality with excellent bow response. 
• Easy playability and comfortable left hand feeling. 
• Damping is optimised for arco, but they also work well for pizzicato. 
• Packaged in uniquely-designed sealed pouches providing unparalleled protection from the elements that cause corrosion.