top p block上垫脚
top engine block模具专上垫脚
top knife block上刀片滑块
Top Boot Block启动模块
leg top-block琴腿托木
top lift block吊杆滑车;顶索滑车
Top junction block上部连接
double-sheave top lift block双轮千斤索滑车
Direction-Modified Open-Top Wedge Block可调向开口式楔板