The Pentel PS513 is a mechanical pencil. It was first produced by Pentel in the 1960s, and is discontinued. Design features include an lacquered long-on-top take on the classic "Sharp" design, a retracting sleeve, and a clearing pin in the p205-style eraser. It is a writing pencil, designed for taking notes or other longhand work, as opposed to drafting, the more common use of 0.3 mm lead.
Other classic designs from this period are the PS535 and the Original Quicker Clicker.
References
Pentel PS513 Wikipedia(Text) CC BY-SA