All our standard hanging ID tags include a pair of heavy duty stainless steel split rings already attached. If these rings become damaged or you would just like extra for any reason (they're great for holding your keys!), you can order more here. Each pair includes 1 mini (12 mm diameter) split ring linked to a main split ring (your choice of 3 sizes). Made in the USA.
Mini split ring (connects to ID tag):
12 mm diameter. 2 mm thickness fits inside our tags' 2.5 mm hole.
Main split ring (connects to collar/harness):
Small = 22 mm diameter. Medium = 25 mm. Large = 28 mm.