The CELO selfdrilling screw special thread for MDF wood, it has been designed with a reduced bit to reduce splitting and bulging of MDF material. SIT recess and narrow countersunk head with milling ribs pulls easily into the material. Included a SIT drill bit in the box. Made of high tenacity steel zinc coating. Reduces splitting and bulging of MDF material when screwing close to the edge or into end grain. Special selfdrilling point with precision placement, allows screwing in without pre-drilling .The partial thread firms tightening of the upper wood layer. SIT recess secures the best screw stick fit, bit grip, no cam-out effect, optimal force transmission.