Need Hidden nut for SRAM Force 1 chainring
The official Sram part number is 11.6918.000.001 , those are said to work on the RED and FORCE models. That is the number for the hidden bolt set anyway. I also read that someone spoke to Quarq and they advised him to pop it out of the old ring and use it for his new ring which he also stated worked just fine, so you may save yourself $20.