The length was just right.
However it is regrettable that there was not mention of "+" "-" "Hex robe" "with hexagon socket" etc. in the item description column.
I should have asked the question first.
This product is + head.
Attaching special rail to square pipe
On 2017-08-21 16:37:58
I was surprised because the head diameter was perfectly fitted to the countersink that was on the special rail.