The 1 1/2" twin HS4 (up to and including 1971) and the twin HIF4 (1972 through 1974) fitted to MGBs used a cable actuated lever type link. With the advent of the single CD175 fitted to the 1975 and through the end of production for North American cars, a part like that was used for the cable. The HIF44 is an SU replacement for the CD175 (44 mm ~1.73") for use on those same MGBs. I'm not so sure that you could even get the CD175 versions used on the MGB even from Burlen these days. There may be something out there that I'm just not recalling, but I don't recall seeing cable drums on other BMC or Triumph cars as stock equipment.