The TARGATT™ CHO-K1 Knock-in Kit (H11) for Antibody Library Screening (FACS) was designed for fast and site-specific knock-in in Chinese Hamster Ovary (CHO) cells using an easy-to-use gene knock-in approach. The master cell line provided in this kit contains the “attP” docking-site engineered into the CHO H11 safe harbor locus in the genome. Any gene of interest can be cloned into the provided TARGATT™ “attB” cloning plasmid, and transfected into the master cell line for generating a stable knock-in cell line. The TARGATT™ integrase-based technology enables efficient DNA integration and high-level gene expression without disrupting internal genes. The TARGATT™ CHO-K1 cell line can therefore be used for uniform, site-specific gene knock-in, generation of isogenic cell lines, and amplification strategies for isolating high expression cells, without the need for single cell cloning.