The D'Addario ECB81 XL Chromes are the company's best-selling flatwound bass strings. With a warm, fat tone and smooth feel that you'll only get from flatwounds, the ECB81 bass strings deliver a rich low-end that makes them ideal for jazz and R&B...though a certain Liverpool pop band made great use of flatwounds throughout their career. The ECB81s are for standard long scale instruments with scale length of up to 36 1/4", meaning they'll fit comfortably with pretty much every standard bass ever made.