This is one of my favorite pens. It is an Indian Handmade Acrylic pen from Gem and co. The pen is called Gama Acrylic Demonstrator. Hope you enjoy the review
The three gamas: Kuyil, Acrylic, Ebonite Jr.
More images of the acrylic demonstrator
Note that a full transparent pen is also available where one can see the nib and feed fully. I however chose a semi-demonstrator pen where the section is black. I do intend to buy the full transparent one later since I love this pen so much.