The TARGATT™ CHO-K1 Knock-in Kit (H11) for Antibody Library Screening (Drug Selection) is 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 knockin 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.