Heavy Duty Solar Road Stud Lights Safety Traffic Markers 6 LED Colours

I bought these a month ago before I returned home to install them. The product is excellent, however, the holes are too close to the body of the light and a normal spanner, socket or even a tube spanner wouldn't fit to fix them to the concrete. I'm trying to find a thin-walled tube spanner for the job. I suggest that the holes be moved a further 3-4mm from the body of the unit.