Pentel PS513 and PS535 automatic pencils. First manufactured in the 70s, they're the mechanical pencil equivalent of 13" and 15" macbook pros. By random fluke,

Pentel PS513 and PS535 automatic pencils. First manufactured in the 70s, they're the mechanical pencil equivalent of 13" and 15" macbook pros. By random fluke, Pentel found a box of 535s in the back of a warehouse and sold them on Amazon a few years ago. The reviews are unreal https://www.amazon.com/Pentel-Sliding-Sleeve-Mechanical-PS535/dp/B00007JQQU/ref=cm_cr_arp_d_product_top?ie=UTF8 https://www.amazon.com/Pentel-Sliding-Sleeve-Mechanical-PS53...