PILOT Vboard Master Chisel Dry... https://www.amazon.com/dp/B09127T1LN?ref=ppx_pop_mob_ap_share

I got these but there are plenty of options. Protip wait longer to change the cartridge. Mine seemed like it needed to be changed as it was thinning. It had a centimeter of ink in the cup. The cups:

Pilot® V-Board Master BeGreen... https://www.amazon.com/dp/B00FX5TPEO?ref=ppx_pop_mob_ap_share

They've survived a month so far and I just went through EdReady precalc.