M4 SOCKET CAP SCREWS HEX HEAD ALLEN CAP BOLTS STAINLESS STEEL DIN 912. M4 - 4mm (Suitable Allen Key Size 3mm). Standard DIN 912. Socket Cap Head Screws (also known as Allen Bolts) present a socket to use with a Hex Key, these fasteners reassembled by using a high-precision machining procedure, allowing tolerances of ±0.13mm to be attained.
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