12 point bi-hexagon.
Spark-resistant tools are used to eliminate the chances of accidental fires or explosions in potentially combustible or explosive environments. They resist the sparks that a standard tool could potentially create when striking hard surfaces. The use of spark resistant tools is essential in many industrial applications such as petroleum and chemical manufacturing, spray booth operations, the marine industry, the mining industry, the paper industries, or any location where flammable vapours or combustible residues are present. Aluminium-bronze spark resistant safety tools are manufactured to 25HRC and offer a breaking strain of 75 - 85kgf/mm2.
Spark-resistant tools must be maintained with special care. Frequent cleaning/re-dressing to remove ferrous particles or contaminants, which may impair the spark-resistant properties, is essential.