The TARGATT™ HEK293 Knock-in Kit (H11) for Library Screening (FACS) is designed for fast and site-specific knock-in in HEK293 cells, using an easy-to-use gene knock-in approach. The master cell line provided in this kit contains an “attP” integrase recognition landing pad engineered into the hH11 safe harbor locus in the genome. The kit also contains a cloning plasmid containing a corresponding “attB” sequence into which any gene of interest can be cloned (under control of the CMV promoter or a promoter-of-choice). The expression of the integrase (provided as an integrase plasmid) mediates the stable integration of the transgene into the master cell line (Figure 1). The TARGATT™ integrase technology enables highly efficient (>40% without enrichment and ~90% with enrichment), and site-specific DNA integration without disruption of internal genes.