G Project - Panel lining! An easy yet effective way to give your models that extra bit of flair. Here are some of the more common options: 1) Panel- lining Gundam Marker (スミいれ用)

Panel Lining for Gunpla 101 - Gunpla 101

Panel Lining for Gunpla 101 - Gunpla 101

Black Color, perfect for most colored surfaces Small sized tip for most normal sized panels From the makers of Mr. Hobby/Mr. Color paints

GSI Creos Black Fine Point Gundam Marker

Panel Lining Gundam / Scale Models with an Ink Pen! Using a calligraphy pen to add details

Gundam Meisters: Gunpla Tutorial: Panel Lining

First time adding panel lines and other details : r/Gunpla

Panel Lining for Gunpla 101 - Gunpla 101

How to Make Your Gunpla Models Stand Out with Panel Lining – LA Scale Model

How To Panel Line a Gundam Model Using a Gundam Marker Pen – Gundam Express Australia

Panel lining is a small detail that makes a huge difference. It's well worth the time, and easy with markers. : r/Gunpla

HG Aerial and my first time with panel lining. Probably not the best kit to be trying it for the first time. : r/Gunpla

A Comprehensive Guide on Panel Lining - Make Your Gundam Kits Look Bet

A Comprehensive Guide on Panel Lining - Make Your Gundam Kits Look Bet

The Gunpla Panel Lining: Gunpla's Guide to Markers and Paints