M3 ; thread pitch 0.5mm, spanner size 5.5mm. M4 ; thread pitch 0.7mm, spanner size 7mm. M5 ; thread pitch 0.8mm, spanner size 8mm. M6 ; thread pitch 1.0mm, spanner size 10mm. M8 ; thread pitch 1.25mm, spanner size 13mm.
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