销孔六角突缘螺帽
hexagon nut with collar and pin holes
销孔凸点
Emboss Phenomenon in Pin Hole
异形销孔
non-cylinder pin hole
non-circular pinhole
oval piston pine hole OPPH
special piston pin hole
noncircular pin-hole
bollard bolometer
Pin-bore1s profile
noncircular pin hole