Flag tag, also known as DDK tag, is a hydrophilic tag for recombinant protein technology with the sequence DYKDDDDK. The structure of Flag tag has been optimized for compatibility with the proteins it is attached to and unlikely to denature or inactivated them. For its high hydrophilic nature, the Flag tag is likely to be located on the surface of a fusion protein, which enables the tag more likely to be accessible to antibodies. This product is generated against 1xFlag tag (DYKDDDDK) and can recognize protein containing one or more Flag tags, no matter it is/they are located at N-terminal, C-terminal or at internal regions. The binding of this product with Flag tagged fusion protein does not depend on calcium ion. The clone of this monoclonal antibody hybridoma is 1E7B4, which is different from any other vendors. This Flag-tag antibody can be used to detect the FLAGGED protein with pCMV-FLAG, p3XFLAG-CMV, pcDNA3.1-FLAG, pef-NEO-FLAG, FLAG-RIG-I, pLenti6-3XFLAG and some other vectors.