WARNING - Not suitable unless wheel diameter (including tyre) is more than 20 inches!
Can only assume that when the product states 'can adjust most wheel between 13 and 15 inches' that it means for metal/alloy wheel rim diameter of 13 to 15" (33 to 38cm)
Even if this product fits your wheel, I think it would only deter an opportunistic thief, not a determined or experienced thief.
Product dimensions:
Diameter (snug fit including tyre) = Minimum 21" and Maximum 28.5"
Disk = 12" (30cm) diameter [this is the full face disk that prevents access to wheel nuts and valve]
Depth = 8.75" (22cm) [inside measurement - i.e. max width tyre accommodated]
Hook = 4.25" back toward axle (may not reach metal wheel rim - so may not prevent removal if deflate tyre)
Material = 17mm x 37mm hollow steel box section (2mm thick walls) - could be cut off by a serious thief, but would discourage most
Weight approx 5.6kg
Further Information:
Product received was a "Roadster" Car Accessories [...] Wheel Clamp (product code 81165c).
Unfortunately no details available at manufacturer site.
No instructions inside box, just one picture on box itself suggesting how to assemble, but assembly is straightforward enough.
Packaging says "ROBUST CLAMP IDEAL FOR CARS, CARAVANS AND TRAILERS" and would be OK as long as wheel is large enough.
I suspect it won't fit most hobby trailers (maybe OK for larger and double axle commercial trailers)