The SB-33 is a small Italian minimum metal blast type anti-personnel mine formerly manufactured by Misar, that entered service in 1977.
The body of the mine is made of two glass reinforced polycarbonate halves, with the top surface having a central neoprene pressure pad.
The combination of low metal content and resistance to overpressure make the mine extremely difficult to remove.
Generally, a small number of SB-33AR landmines would be sown inside a minefield containing standard SB-33 mines in order to hinder and deter any attempt to conduct demining operations.
However, uncleared minefields containing SB-33 mines do exist e.g. in Afghanistan, Djibouti, Iran, Iraq, Kurdistan, and the Western Sahara.