The gas line in my kitchen feeds my stove through what looks like a .873" pipe (measured outside threads). The female end of my stove's flex-line is 15/16" (I think). Do you sell adapters to fix this issue?

The guy above hit it on the mark

.873 is most likely standard 3/4 inch pipe and it sounds like a standard 3/4" flex line as well. The flex lines work with a flared compression fitting which comes with the flex line most of the time (some plumbing supply warehouses only have the flex line with a flared valve on one end and flared compression fitting on the other) if you get the 3/4 flex line and an extra 3/4 compression fitting you should have everything you need. Remember dope your joints. Not sure what your trying to do but they should have what your looking for.