Button Head – BHCS
Allen Button Head BHCS
The Socket Button Head Screw design is primarily used where a lower profile head is required and for aesthetical reasons.
These screws can take a lower tightening torque as compared to the DIN 912 screws. 
Flange Button Head Allen Screw 
Low profile head facilitates space saving and safety.
These are protective fasteners which provide the assembly with structural support as well as a visually appealing look. It protects the components around it from damages like scraps and unintentional cuts.
Another advantage of these screws is the large under head bearing surface – this eliminates the need for washers. The Flange distributes the pressure better.
Flanged Button Head TORX Screw ISO14579
This is an improvement on the Allen drive option and provides a more reliable slipless fixing using lesser operator effort.
The Low profile head facilitates space saving and safety.
The flange eliminates need for a washer.
Not only will this make sure even load to the target surface, this will help to prevent the screw from loosening and ensure good grip to the material in which it is fastened.
This property makes this head style suitable for fastening softer materials.