the zinc plating can help it perform durably and stand up against the elements over the long-term

Marine screws are locked in place thanks to their "teeth" (the thread indentations will resist back-out even after prolonged vibration)

1 1/4 x 18 ITM SDS Plus Hammer Drill Bit X-Cutter

1/4-20 x 8 Socket Cap Screw Alloy

M30-3.50 x 60 Socket Cap Screw 12.9 Alloy Plain DIN 912 Finished Hex Nuts 316 Stainless Steel the zinc plating can helpM30 3. 50 x 60 Socket Cap Screw 12. 9 Alloy Plain DIN 912 . Alloy Socket Head Cap Screws from Brighton Best. Hardness of RC 38 43, meets or exceeds DIN 912. Manufactured from heat treated alloy steel, 1960 series.