On "Unbreakable Pencil" - a marketing scam

"sleeve position" is all that is about. Various makers provide totally contradicted theory for "lead protection": 

- with lead exposed out of sleeve while writing:

Zebra Delguard ( circa 2011)

Rotring:

https://www.rotring.com/pens-pencils/mechanical-pencils/rotring-600/SAP_2114264.html

- with lead inside of sleeve while writing 

Pentel Orenz (circa 2022)

Uni Kuru Toga Advance (circa 2022) - retractable sleeve

- Never mention a word about Lead Protection: 

Uni Kuru Toga Dive 5000 (circa 2022) and many others, e.g. Pental other than Orenz. 

Reference: 

Zebra: https://www.zebra.co.jp/pro/del_guard/?tab=oc-nav-sustainability

Pentel: https://www.pentel.co.jp/products/mechanicalpencil/orenznero/

Uni 559: https://www.mpuni.co.jp/products/mechanical_pencils/sharp_pen/advance/advance.html

Uni 5000 Dive: https://www.mpuni.co.jp/products/mechanical_pencils/sharp_pen/kurutoga/dive.html