A few years back,I was at a swap meet in England when I spotted a Vertex mag.It looked like it would fit my B engine .It still worked so I bought it for the equivalent of $35. Unfortunatly the cap broke in transit so I am still in need of one.The mag fit the B just fine.---Cap says*Vertex Scintilla British made CP62010* Data plate*Scintilla Ltd NV4R 480-1960-13*.