This is a small to medium-sized potter wasp, usually 14 to 17mm; males are smaller. This is one of the stout-bodied species. It is mainly yellow-brown, with a faint pair of curved markings on the thorax. There is a thick black band on the second abdominal segment.
This species is sometimes referred to as Rhynchium brunneum. Due to the fact that I couldn't find any info under this name, and that this species is considered Rhynchium quinquecinctum in Taiwan and Mainland China, I stick with the latter for now.
This is a fairly common species in Hong Kong during the warmer months. It frequently appears in urban parks. However, I have not been able to find out what type of prey it uses, or its typical nest site.