YDC series jack is a PC card before feedthrough jack, used for stretching a single strand and pretension prestressed single strand and release Zhang. This series of jack just replace the clip on different tools, you can separately tension φ12.7, φ15.20, φ15.7 of single prestressing steel strand. YDC240QX-type jack is a PC card before feedthrough jack, transferred to a single PC strand tension. Top-pressure device with dedicated 4-500 Type S with the electric pump can be the top three oil pressure 14KN, 15mm stroke. For use: flat tension anchor, tensioning the anchor hole, the anchor group of single strand of pretension, the anchor group released a single strand Zhang.