The D'Addario EXL170BT is one of the most popular bass string in the market. The gauges are mathematically optimized resulting in a balanced tension that gives you greater control and more comfort on your style of playing. It combines a very unique bright booming tones with greater dynamic control and even between strings great for fretting, plucking and slapping. String gauges wound .045, .060, 080 and 107 Made in the United States.