Currently locked in a knockoff CB6000s which fits well, 3.25 inches total including ring and gap, using a 1 & 7/8 inch (47mm) base ring. Would like something a bit more open for cleaning without the need to unlock. I have a high and small right nut so probably could do with a hinged or modular ring. Open to any material but something discreet for gymwear. I'm in the UK. Thanks all.