The Sacless Blackbird Fountpen BT200/82 by Mabie Todd c1937-1940. Today's pen is one we would call very uncommon, if not rare in the USA, the Mabie Todd Blackbird Topfiller. In their own advertising, Mabie Todd called this pen the Sacless Blackbird Fountpen. The pen is similar to the larger Visofil VT and shares the visual ink reservoir in the barrel. It has a similar plunger fill system as the Visofil VT, with the plunger hidden under a long blind cap. The plunger mechanism is a spring wrapped with a sac to seal the end of the pen, acting as a diaphragm as the plunger is pumped, a similar operating principle as the Parker Vacumatic. The Sacless Blackbird came in three colors, Black and Clear, Green Gold and Black, and this pen, model BT200/82, in Blue Gold and Black. They sold for 7'6 in the United Kingdom and had matching pencils. When World War II broke out, the Mabie Todd Harlesdon Factory was destroyed, so repairs to these pens were done by replacing the plunger unit with a simple ink sac squeeze bulb.
