The guard arrived along with a few other item and unfortunately it had been damaged because it's just packaged in a little plastic bag and obviously one of the heavier items and caused a crease across the guard, I was able to straighten it but it's not perfect.
The description for this item doesn't mention the dimensions so for your information it is a thin piece of metal approximately 0.2 mm thick.
Approximately 80mm x 22mm.
The slot measures approximately 3 mm x 69mm.
The slot is not terribly consistent and is a little wider in the middle but this may have been caused by the guard bring damaged in transit.
The guard appears to have been punched out from a sheet rather than being laser cut so the outside edges and the slot are not very well finished with rough sports all the way around, you would need to be careful using it in case it damages a lacquered fingerboard so best to put the smooth side down so the rough side is up but then you need to mind your fingers !
Tried on a selection of guitars, fenders and Gibsons and the slot at 3mm is really too wide as there is space on each side of the fret so the fingerboard isn't protected which pretty much defeats the purpose of using a guard.
I had considered the Rockbag fingerboard guard models and I think they would be better as you can choose the width of the slots from 1.8mm, 2.65mm and 3.15mm, also they come in pairs and are made to be held in place with elastic bands, I think having tried the Göldo version the Rockbag guard looks like a much better product.
The Göldo was a disappointing purchase.