人妻熟妇少又伦精品视频,玖玖伊人色,天天做,天天射,韩日,www.色视频,四虎成人www国产精品,69av在线,色就是色,欧洲色图

This product is a kind of damper dependent with velocity,and includes cylinder,piston,fluid,piston rod,sealing materials,and etc.It can decrease bridges’ damage and subsequent mechanical displacement when earthquake occurs.Products comply with:JG/T 209-2012 Dampers for vibration energy dissipation of buildings.