Screw used for fastening flywheels or crankshaft flexplates.
Bolts used for tightening single or dual mass flywheels paired with manual transmissions, or automatic gearbox connection plates.
Very compact bolts for working in tight spots, they must withstand the maximum possible load in order to ensure that power is properly transmitted from engine to transmission.
In almost all cases they have a 10.9 strength rating and increasingly more a 12.9 rating. They are more and more designed with custom strength ratings, even with very narrow Rm ranges.
They work in the plastic range and are usually tightened based on torque + rotation. They have an external driver head, never require a washer. They must not have any tendency to come loose, thus they are manufactured with plastic blocking components in almost all cases.