I got the set at New York comic con, they're panel line markers... (Link on amazon,) https://www.amazon.com/dp/B00N2DCWLC/ref=cm_sw_r_cp_api_RjP4zb7W0G8BW You can look up a vid on you tube. they're really awesome. I 100% recommend them... And thanks, he's a really good boi.
GSI Creos Gundam Marker Pouring Inking Pen Set https://www.amazon.com/dp/B00N2DCWLC/ref=cm_sw_r_cp_api_glt_i_2XC4R8ZPANK22EBWQY99
This pack is great, has multiple colors of the flowing kind. I’ve only had to restock the black one ever though. Different colors of panels liners can look really great on certain colors as opposed to just always using black/grey.
I just got this one to try out different colors and it includes an eraser pen as well: https://www.amazon.com/gp/product/B00N2DCWLC/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1
But to be honest I prefer using my zippo lighter fluid. You rub a bit into a q-tip to clean. It's really easy.
Video for example around 15:37 for the Panel Lining+Cleaning: https://www.youtube.com/watch?v=Hwu_EXr-cmM&t=1s
GSI Creos Gundam Marker Pouring Inking Pen Set https://www.amazon.com/dp/B00N2DCWLC/ref=cm_sw_r_cp_api_glt_i_2XC4R8ZPANK22EBWQY99
They are the 300 series of Gundam Markers, here's a link to the full set