Commonly called mechanical pencils, these make sketching or writing in the field clean and easy. Leads can be inserted into either end, just slip the ring down to tighten around the lead. These are handmade out of brass.
Small: 4" long - single-sided lead
Large: 7" long - double-sided lead.
Love the little bit of HC kit. It goes well with my journal to make a realistic traveling kit.
I’ve been taking drawing classes with 5.6 leads and this is a better option than the thick lead holders available, It has balanced weight and feels like a brush with very expressive and fluid marks.
Still use this almost daily in my drawings. I love it so much it actually motivates me to draw more because it’s so cool.