The Pilot H-327 is the main mechanical pencil that I've been using for years. I remember writing a review for it before but for some reason I couldn't find it again.
The Pilot mechanical pencil is actually available in 4 different sizes, 0.3, 0.5, 0.7 and 0.9mm. Their product codes are H-323, H-325, H-327 and H-329, and body colours are yellow, black, blue and orange respectively. I've three of them, the 0.3, 0.5 and 0.7mm
I like the pointed tip of the pencil. Unfortunately, it doesn't have a rubber grip so it's not as comfortable to hold as compared to mechanical pencils that do have them, such as the Staedtler Mars Micro 775 which I also have.
The back is very typical with a cap that hides the small piece of eraser which I think is not replaceable.
It's a very hardy mechanical pencil. Lightweight and seemingly very durable. Compared to other brands, I like that you can differentiate easily the different lead sizes by the striking body colours of the pencils.