Assembling the WaterRower Natural rower typically takes less than an hour, and the included 5 mm Allen key is all you need to get the job done. The unit only weighs 66.5 pounds, and it comes partially assembled in two boxes. The heavier of the two measures 29” x 24” x 23” while the lighter box is long and contains the two rails. Most people can assemble unassisted in as little as 30 minutes.