The 10P13 is an output valve, designed for television service in both audio and frame timebase circuits. The 100 mA heater chains were used in post WWII monochrome receivers where few valves were needed. The 2.6 Watt output would have been more than adequate for domestic use.

This valve also appeared with an IO base as the 10P14

The thin glass tube envelope is 20 mm in diameter and, excluding the B8A base pins, is 61 mm tall.

References: Datasheet & ¹⁰⁴⁰. Type 10P13 was first introduced^¶ in 1948.

 
Pin Connections

B8A	1	2	3	4	5	6	7	8
	h	a	ic	ic	g2	g1	k	h

 
Absolute Maximum Operating Conditions^¶

Beam Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm	Pout	D
	40	0.1	180	150	-6.3	29	5.8	7.5	2.6W	10%