I was told, last year, by staff at the USFS White Mountain station that the Ursack was allowed in Inyo County. I have been using it for several years in Inyo County. However, once you leave Inyo County into other areas, like over Bishop Pass into Seki, or Yosemite, the rules change. Call the Bishop USFS White Mountain station office for confirmation. Don't be put off by hesitant USFS staff, because the regulations say "bear resistant", not "bear proof". No container, hard sided or otherwise, is "bear proof."
https://ursack.com/pages/where-ursack-is-approved
