The No1 Mk.IV is the standard issue NBC/CBRN suit for the Australian Defence Force up until its replacement by the CQC "Targa" CBRN Suit during the Land 2110 CBRN overhaul project

Manufactured by Remploy, which is now a subsidiary of OPEC, the suit is designed to work in conjunction with the S10/ADF-10 Respirator, NBC gloves (Both an 'inner' white cotton glove and a outer rubber glove) as well as NBC Over-boots. The suit is manufactured out of a charcoal impregnated fabric, and it is split into two parts, the smock and the trousers. 

Two different coloured suits would be issued with the Australian Defence Force, being the regular DPCU version that is commonly seen, as well as a lesser known grey version that would exclusively issued to the Royal Australian Navy. 

This suit was also used by the British Armed Forces in both the DPM and Desert DPM patterns