https://www.jpcorry.com/jp-corry-products/rockwool-pwcb-cavity-barrier/
Rockwool PWCB Cavity Barrier
Description
Thermal Cavity Barriers - Tcb (Thermal Cavity Barrier) And Pwcb (Party Wall Cavity Barrier) - Have Been Developed To Exceed Minimum Building Regulation Requirements For Fire Resistance Within Concealed Wall Cavities.