The 5881 is a very reliable tube that is widely used in many current production tube amplifiers. It has a warm tone with good 'bite.' This modern version is able to tolerate higher voltages than its 5881 / 6L6 cousins. The Sovtek 5881 delivers a warm, round tone that "sweetens" any vintage or modern guitar amp design. Built to rigid military standards, the 5881 will tolerate higher voltages than any other 6L6.