This unit demonstrates the concept of a lamp within a circuit. Can be used inline with other components of Eisco Series PH1029. Two 4 mm Terminals for banana plugs. Accepts size E10 Screw bulbs - Miniature Edison Screw (MES). Max voltage: 6 volts. Bulb not included. Base Measures 3.75" (95.25mm) x 2.75" (69.85 mm) x 1.38" (35 mm). CE Certification. Power Source needed for operation. An economical Eisco power source is PH0971DCAC which is not included. Eisco offers a number of different voltages of replacement bulbs that will fit in this holder ( PH1014A 1.5 Volts Pack of 10, PH1014B 3.5 Volts Pack of 10, and PH1014D 6 Volts Pack of 10) Not included with this listing.