The 30mm Erdanker JF type anchors have a flange on the top with the bracket being attached to the structure first, they are then hammered through the slot, effectively nailing the structure to the ground. Ideal for lighter items such as benches, garden furniture, also great for temporary fixing such as at trade shows, no damage is done to the ground on removal and they are just unwound with an adjustable spanner if they need repositioning.