This is a lot of 4 new M5 x 27mm x .8 pitch titanium aerospace grade Ti6AL4V screws. Use these where you need a high strength, light weight, corrosion resistant fastener on bicycles, motorcycles, aircraft, race cars, or your very own rocketship. Head diameter is about 8.59 mm. Everyone knows about the high strength to weight benefit of Titanium, but also remember that Titanium is essentially immune to corrosion. Check your size needed carefully, I have these available in 10mm, 13mm,15mm, 19mm, 22mm, 23mm, 25mm, 27mm, 29mm, 36mm, and 44mm lengths. Also I have available in my store a 15mm long version with a wider posidrive head (sort of like a Phillips #2). These are actually Aerospace Surplus bolts not to be confused with cheap imports. These screws come with a dry lube coating as Titanium has a tendency to gall under some conditions. You do not want that on your expensive frame, aircraft, or race hardware! If you wish the dry lube can be removed with lacquer thinner or nail polish remover. Or you can just remove it from the head for titanium aerospace bolt look and leave the threads protected. Last photo shows a bolt with the dry lube mostly removed showing natural finish Titanium. Heads are drilled for lockwire provision. Use an M5 spline or T27 Torx bit for installation. These bolts are surplus from the US Space Program. These are in stock and ship from the US to worldwide destinations.