成人毛片在线观看,日韩在线观看免费完整版视频,日韩不卡,国产精品久久亚洲一区二区,日韩在线视频精品,天天做天天爽,国产性夜夜春夜夜爽三级

PD type parallel clavis belongs to the connection fittings in power fittings. PD type parallel clavis is used for connecting single boards to single boards and single boards to double boards, and can only change the assembly length, not the connection direction. Parallel hanging plates are often made of medium thick steel plates through stamping and cutting processes. The standardized parallel hanging boards are divided into single board parallel hanging boards, double board parallel hanging boards, and single board converted double board parallel hanging boards.