A pair of rings that flank the site of cell division, formed by splitting of the septin ring (or collar) prior to cytokinesis; this double ring structure is thought to trap proteins needed for cytokinesis or the formation of the new membrane or cell wall between the two septin rings. Split septin rings are known to occur in budding yeast cells and probably occur in other cell types as well. [ http://www.ncbi.nlm.nih.gov/pubmed/16151244 http://www.ncbi.nlm.nih.gov/pubmed/16009555 ]