99% sure that QBP (Quality Bicycle Products) was/is just the distributor and Vuelta is the manufacturer of this "Engagement Ring" (clever branding, huh?)
Vuelta still make some similar flat (no pins or ramps) rings in the USA but I believe this (the OP's) model has been discontinued.

catalog page for their current offerings in 110 BCD: https://www.vueltausa.com/components...mm-34-60t.html