Carpet extractor attachment for Kärcher wet/dry vac (35mm)

An attachment to use with a shop vac with a 35mm nozzle (eg Kärcher, but possibly others), useful for wet cleaning carpet and upholstery. The attachment area is conical so it creates a snug fit.  Print with 100% infill, this needs to be as strong as possible to prevent collapse under vacuum. No support needed.