1、100% brand new and high quality. 2、These self-drilling screws has pointed drilling tails, no need of auxiliary processing. 3、They can directly drill, tap and lock on material at the same time, safe and easy to operate, greatly saving construction time. 4、 Compared with ordinary screws, they have high maintenance force, and will not be easily loose for long time. 5、 Mainly used for fixation of color steel tile in steel structure, or for simple construction of thin sheet. Features: 100% brand new and high quality. These self-drilling screws has pointed drilling tails, no need of auxiliary processing. They can directly drill, tap and lock on material at the same time, safe and easy to operate, greatly saving construction time. Compared with ordinary screws, they have high maintenance force, and will not be easily loose for long time. Mainly used for fixation of color steel tile in steel structure, or for simple construction of thin sheet. These screws cannot be used for bonding between metal. Specification: Material: Zinc plated iron Head Type: Flat (countersunk) Size: M4.2*13, M4.2*16, M4.2*19, M4.2*25, M4.2*32, M4.2*38, M4.2*50 (Optional) Quantity: 50pcs Weight: 46g~161g / 1.6oz~5.7oz (approx.) Package list: 50 * Screws