One Lucas Type Single Pole Bulb Holder ref 518042 for Triumph:

TRIUMPH SPITFIRE MkIV & 1500 1970-80.

TRIUMPH GT6 MkIII 1970-73.

TRIUMPH TR6 1969-76.

TRIUMPH STAG MkI & II  1970-77.

TRIUMPH DOLOMITE 1300, 1500HL, 1850, 1850HL & SPRINT  1972-80.

TRIUMPH 2000, 2500 & 2.5PI Mk2 1969-77

OEM Reference 518042

Push fits into the rear lamp base usually operating the indicator or reverse lamp bulb.

The price is for ONE bulb holder and there are 4 required per car, 2 per rear lamp.

May fit other classic cars and commercials.