The AP Toxic Shocker is one of the latest mop markers from Art Primo. This marker has about a 3/4 ounce capacity. Although you can use whatever ink you want in this marker, we would highly recommend using an alcohol or dye based ink. Try using Pilot Ink, Molotow ONE4ALL Ink, or Smash Ink. It has a similar nib to the Art Primo Drip Mop Mini. This marker ships EMPTY. The nib can easily be replaced.