The pen for your tablet is LP1100K, and if you live in the USA you can get an original replacement here:
https://www.amazon.com/-/es/Wacom-LP1100K-Bolígrafo-tableta-Intuos/dp/B07CYRWTZF/ref=sr\_1\_1?\_\_mk\_es\_US=ÅMÅŽÕÑ&crid=2JGS6Q1233CIX&keywords=LP1100K&qid=1674083000&sprefix=lp1100k%2Caps%2C141&sr=8-1