The Antiviral kit MK-2 was manufactured by The Hyland Organization for Rakghoul Neutralization (THORN). It provided temporary immunity to the rakghoul plague as long as it was equipped. The Antiviral kit MK-1 was a weaker version and the Antiviral kit MK-3 was a more powerful version. Captains Erimus Moayoi and Lahoa Diatog of THORN sold Antiviral kit MK-2s.