Yes The retention force of peek clasp is lower than that of Co-Cr clasp. In order to improve this problem, Weld company added 20% ceramic particles with diameter less than 0.5 micron, and the position of PEEK bonded bridge clasp can be painted with porcelain. Polyether ether ketone (PEEK) is a special polymer material, which consists of repeating units with one ketone bond and two ether bonds in the main chain structure.