Sparklets Collectors Guide code: SCG/BUC-03
Bulb: Size D, unpainted
Packaging: Cardboard box containing 12 bulbs. Vertical opening.
Box design: 12 “Prana” Sparklet “D” (Refillable) Bulbs for use with “C” Syphons only
Fits: “C” Syphons
Bulb Length: 67mm
Notes: This box cost 2/-, but if you returned the empty bulbs in the original box you are allowed 6d off another box!
It is the earliest size D bulb I have found so far.