Kli Rishon and Kli Sheini (Bitul and Blios #51 - Shulchan Aruch YD 105:2)
Rabbi Dovid Cohen
Kli Rishon and Kli Sheini: Basic halacha; Exceptions; Defanos Mekariros; Irui kli rishon; Tunnel Pasteurizer. See seforim by Rabbi Cohen at www.kashrushalacha.com