The pen is a simple eyedropper clear demonstrator. Meaning.. no cartridges to fill, no piston convertors to use. simply open up the barrel and fill it up by pouring from your bottle :)
This is now my daily sketch pen. I can fill up the huge barel with almost 3 cc (maybe more) of ink, and keep going for ever.
After doing some research I found that this pen is made by a company called the Airmail pen co. in Mumbai and they have been at it for more than 50 years! They have quite a range. The one I had purchased in known as Wality 70 JT and it is Huge! it also has a variant where the barell is covered except for a window to show the ink. Though I love the fully transparent version, where I could see the ink swishing and splashing around likes the waves on the beach.
Now comes the sweet part. This pen cost me Rs. 100 ( $2) and a bottle of black ink that cost me Rs. 12 (30 cents). My best buy in Fountain pens.