For testing, I've tried other shoes from me on the stretcher:
My little "out Latsch direct" Lloyd shoes size 46 (11) - with which I am very happy for 3 years and have a new sole - on the other hand to do something difficult. The Spanner is a little too small for this. But since these shoes eh soon faded away, I'll stay with the old releases.
For another couple Lloyd Shoes (Model "denier" relatively pointed forward) in the size 46.5 (11.5), the clamps are also too small, and here I would also order one size bigger.
In short, if you have found the right size (and this is quite easily possible using the product description), you have a super shoe tree with 3 years warranty!