These hook clamps are from the reputable Doughty brand, however their slightly different shape means that there is a smaller than usual gap between the curved end of the clamp, and the base. This makes it difficult to get the clamp on to the lighting bar without loosening the main suspension bolt (the bolt which holds the lantern to the hook clamp). In future, I would buy the squarer version. Of course, you could use shorter M10 bolts to get round this, if you have them