This detachable, light weight pickup design was ingenious. The whole arm could be unscrewed and changed at the mounting base. Arms were sold for 78rpm play using miniature thorn needles or sapphire and also sapphire for "Microgroove" records. These examples come from a rusty DR14 reproducer.
£6.10.0 + pur tax £3.5.0, matching transformer £2.2.0, pre-amp stage £5.10.0