Because chain link fence posts are hollow

Attaching a male hinge with a female hinge allows the gate to swing back and forth

The hinge is used on an ornamental iron fence

This is a galvanized steel 6" Square PS Caps

2" x .090 x 8' CR20 Commercial Galvanized Pipe for Chain Link Fences cfp_related_corner_post_5_Ornamental_Flat_Top_Fence Because chain link fence postsThis is a 2" x . 090 x 8' CR20 Commercial Galvanized Pipe for Chain Link Fences. 2" nominal O. D., 1 7 8" actual O. D. . 090 wall thickness Cold rolled 20 weight Galvanized steel Made for commercial use Pipe must be cut down to lengths shorter than 8' or shorter to ship UPS, otherwise it would need to be shipped via a flatbed which is much more expensive. This pipe can be cut to customer specifications. Cut charges may apply.