Countersunk hex socket bolts manufactured to DIN 7991, made from carbon steel to property class 10.9, with a black oxide finish. This pack holds 10 bolts in M8 x 25mm. Also sold as countersunk machine screws, socket screws, allen bolts, allen head bolts and black socket screws.The head is a conical 90 degree countersunk profile that seats flush with, or just below, the surrounding material once driven home, for a smooth, snag-free surface with no proud bolt head.The Allen recess allows convenient screwing and tightening with an Allen wrench, so installation needs only standard tools. The socket is fully recessed, so you tighten each bolt straight down its centre with a 5.0mm hex key on this size, which also helps where a spanner will not fit.The conical shape facilitates screwing into materials and allows for fastening in hard-to-reach areas. Every size is threaded along its full length, and each bolt pairs with a tapped hole, a standard nut or a threaded insert of the matching metric thread.Where it fits: flat-pack furniture and cabinetry assembly, where a flush head avoids snagging on clothing, hands or adjoining panels; 3D printer and machine frame builds, which suit a compact, fully recessed drive; electronics enclosures, where a smooth external profile matters for appearance and safe handling; and general workshop and DIY fixing jobs that call for a high-tensile, low-profile fixing driven with a simple Allen key.Choosing the size: ten sizes run from M4 x 8mm to M8 x 35mm, in steel bolt packs of 2, 10, 50 or 100. Hex key by diameter: 2.5mm for M4 bolts, 3mm for M5 bolts, 4mm for M6 bolts and 5mm for M8 bolts. Countersunk bolts are measured by total length, including the head. This pack is M8 x 25mm, 10 bolts.Specification: countersunk hex socket bolt to DIN 7991; carbon steel, property class 10.9; black oxide finish; thread M8 x 25mm; fully threaded; head diameter 16.0mm (0.63in); head height 4.4mm; hex socket size 5.0mm; 10 bolts per pack.