This part is associated with Zinc Finger Transposase devices
A zinc finger transposase is an engineered protein derived from a zinc finger DNA binding protein and a transposase. A transposase is an enzyme that reacts with DNA at specific sites and then clips that DNA region out of the source DNA forming a "transposome". This DNA/protein complex is highly reactive towards other DNAs. It reacts by inserting the DNA sequence mostly randomly into the target DNA.
Zinc Finger proteins (ZF) are DNA binding proteins. The special thing about them is that 1) the ZF's bind long sequences of DNA, long enough that it might be unique in a eukaryotic genome, and 2) zinc finger proteins that bind to most sequences can be generated somewhat easily. By fusing ZF's to transposase, you can recruit the transposome to a specific site in the genome and thereby bias the insertion site of a transposome into a cell's genome.
You should read the following papers
References: PMID 11821858, PMID 17344320, PMID 19965773