The 5687 is a special quality double triode. It is described as a general purpose medium gain triode pair with good emission. The pair can dissipate 7.5 Watts or a single triode can dissipate 4.2 Watts.
The Tung-Sol name. The cathodes are rectangular and the control grid is wound on copper rods.
The heater can be seen to be formed into four loops and with 900 mA of heater power the cathode emission is considerable as stated in the data-sheet.
The grid axis is at right angles to the anode side flanges. This arrangement gives maximum cooling from the point with greatest electron bombardment.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 46 mm tall.
References: Data-sheet & 3002. Type 5687 was first introduced in 1956. See also1956 adverts.
