This pen is from the personal collection of Kawuska - an FPN member that has inspired many of us with his pen collection, photography, and craftsmanship in penmaking!
Reflex was a sub-brand offered by Montblanc from very early in the 1900s, but sales really picked up in the 1920-30s. I have seen models on the internet and in books made of hard rubber as well as celluloid. Reflex pens came in a variety of colours like coral red, azurite, marbled gree, and black. Propelling pencils were manufactured too.
This particular Reflex 'C' pen was produced between 1929-34. The total length of the pen capped is 12.35 cm with the cap OD at 13.28 mm. It is the largest size in the series, with the model 'A' and 'B' as smaller variants.
Just look at the clean lines on this pen with the flat top, and the contrast of red and black... So beautiful!
This pen has a period-correct heartholed 14c nib. Reflex pens came with several kinds of nibs. A collage of pics from the archives of penboard.de show examples with a steel "reflex" nib, the typical tier-3 warranted 'b' nib, warranted square imprint nibs with and without numbers inside, and even a glass nib.
Some models do come with clips including typical tier-3 clips and even the teardrop clip without the "Montblanc" imprint. However, this 'C' model has also been documented as coming without any clip.
The Reflex 'C' is a button filler. But, I have seen documentation of other Reflex models made with safety filler and button fillers too.
A Montblanc catalogue from the 1930s positioned the Reflex as a student pen. These pens were meant to be for the lower price market - whether for children or adults. However, as collectables they rather valuable today. Collectible Stars I rates the smaller 'B' model in coral red as 11 out of 12 points on rareness with an estimated 10 or so models to be found. I would expect the larger variant that we have here to be as - if not more- rare!
Rösler, J., & Wallrafen, S. (2014). Collectible Stars I: 1908 - 1947.