Choice of M4, M5, M6 & M8 internal threads. Installed by simply screwing into a suitable size hole. M8 x 13 11.0 - 11.5mm. M8 x 20 11.0 - 11.5mm. M8 x 25 11.0 - 11.5mm. M4 x 10 5.6 - 6.0mm. M6 x 10 8.7 - 9.1mm.
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