The Montblanc Simplo No. 30 is a early-1930s Meisterstück flat-top distinguished by its push-knob filling system—a short-lived, clever variant where the end knob becomes the “button” you press to compress the sac. That makes the 30 a fascinating transitional model between Montblanc’s earlier eyedroppers/safeties and the piston fillers that soon defined the brand. Examples appear in hard rubber and striking celluloids (coral red, black-and-pearl, azurite, etc.), usually with the snow-cap emblem and “4810” nib imprint; production occurred in Germany in the early 1930s and continued with Danish-made variants later in the decade.
Equally interesting is what its imprint can tell you about the company. In the No. 30’s core production window (roughly 1932–1934), the firm was still legally the Simplo Filler Pen Co. GmbH; in 1934 it adopted the name Montblanc-Simplo GmbH. So a Simplo-only imprint generally points earlier, while a Montblanc-Simplo imprint suggests the changeover era. That name history also mirrors the brand story: “Montblanc” had been the flagship name since the 1910s, but the corporate rename lagged until 1934.