The height of each ring is as follows:
Low - 0.775", Medium - 0.950", High - 1.100".
Centerline height from top of rail: Low - 0.950 in Medium - 1.100 in High - 1.250 in that's right off wheelers site
Tiffany S answered just to make noise and caused me to order a ring that will not work for me. The actual caliper measurement of the 35mm low rings is .938. According to wheeler customer service response to questions posted on their website, 30mm rings are .875 for low, .950 med and 1.1” for high. I can’t confirm if these numbers are accurate but I would think so.