Hi, I want to know the name of this metallic device used to hold and attached one side of a tennis net to one of the poles. The centre of the device can be twisted to tighten the tennis net. Anyone know the name of this particular device I am speaking of? And most importantly, where can I buy one of them? I need it because without it my tennis net is too long for the two poles and the centre of it just sags to the ground.