Rat-Ring Trim Ring is a transition trim ring that has approx 22.5 mm opening for you atomizer.. It has a heavy radius like the dot drip tip i made earlier.. Outside diameter is approx 25.5mm (26mm).. sitting at approx 4mm with the heavy radius it looks skinny;) or choos the 22~24 ish mm for the slimer approach!! oh so cute!!.... Made from Delrin and offered in Black or White for now!!