Can they be used on 4 x 4 posts?
Yes, they an be used on 4" x 4", 2' x 4", 2" x 6" as well as slides and climbers. Hardware is included to mount on all these different types of surfaces.
What is length?
15" long.
What is diameter of rod?
3/8".
Can these be used on metal swing sets?
These are intended for wooden playset structures.
How do the anchors attach?
You attach the anchors with a lag screw (included) and a wood post/base and with a bolt, nut & washers (also included) on a slide or climber .