M Wave Adapters for 10mm Solid-Type Axle for Single 40 Trailer

I recommend this product

Purchased for use with an unbranded, single wheel trailer, which is effectively identical to M-Wave single wheel trailer (different colour paint scheme).

They screwed onto the solid axle fine, but you could see that the threaded holes had not been drilled in perfect alignment with the shaft. This doesn't seem to be an issue though.

Have worked well enough for a number of short distance trips carrying reasonable loads (10-15kg).