"These are good, simple hinges. One of the hooks on mine was slightly out of true with its backplate, which was irritating, but no any kind of problem since the gatepost is far worse!
A tip for young players - the square hole right at the base of each band is there to tighten the band around the hook to make the gate secure. So leave that bolt loose until the gate is in place. You then tighten the bolt to tighten the band around the hooks, making the gate difficult to lift off the hooks. To remove the gate, loosen the bolt and slide it upwards.
A little grease on the hooks before mounting the gate is a good idea too."