CELO chipboard screw VELOX SIT made of stainless steel with Eropean Technical Approval for use in timber construction is very suitable for outdoor applications. The SIT recess guarantees a perfect power transfer and a long-lasting SIT bit. Due the conial recess the screw will be centerd (no tumbling) and sticks on the bit, so you get large improved working comfort. TX bits can also be used, but without the mentioned advantages. The patented tip thread area for no splitting and reducing installation torque. This is for a flushing screwing and a longer battery life. VELOX SIT is sliding coated for a additional torque reducing.