The 6E5S is a Soviet-manufactured, glass, octal-base (8-pin) electronic light indicator, commonly referred to as a "magic eye" tube. It serves as a direct functional equivalent to the 6E5G, 6G5G, and the original American 6E5, providing a visual tuning or level indication.

Primarily designed for superheterodyne radio receivers, the 6E5S offers a clear visual representation of signal strength for precise station tuning. Beyond radio applications, it is also well-suited for use as a recording level indicator in tape recorders, as well as in transmitters, audio amplifiers, and various measurement instruments. The display features a distinctive glowing green fluorescent target that produces a dark "shadow" angle; the width of this shadow narrows as the signal strength or control grid voltage increases, closing completely when the signal reaches its maximum. The rich green glow and responsive shadow movement make the 6E5S a highly desirable component for restoring classic radio equipment or adding a distinctive visual element to custom audio projects.

Technical specifications:

• Heater voltage: 6.3 V
• Heater current: 300 mA
• Anode voltage: 250 V
• Target voltage: 250 V
• Control grid voltage: -4 V (nominal)
• Anode current: 5.3 mA
• Target current: 5 mA
• Sensitivity: 1.2 mA/V
• Gain: 24
• Minimum operational lifespan: 500 hours