to throw away the card if the value goes negative when fare is calculated on exit. The $3 fee is waived if the card is registered for Autoload at the time of purchase (in which case it cannot go negative). There is no fee to transfer plastic Clipper cards to mobile wallets. The $3 fee for new virtual cards in mobile wallets was waived for the first six months following launch but came into effect on October 15, 2021. The fee was temporarily waived again beginning in March 2022 due to supply chain issues reducing the availability of plastic cards. Adding money and transit passes Passengers can add money and transit passes to their Clipper cards in person ("at participating retailers, participating transit agencies' ticket vending machines and ticket offices, Clipper Customer Service Centers, and Clipper Add Value Machines") at work, automatically, online, or using the Clipper mobile app. While money and passes added in person are available to use immediately, doing the same by telephone, online, or using the mobile app may take 3–5 days to register on a physical Clipper card. Cash value and passes added online or via the mobile app to virtual Clipper cards in Google Pay or Apple Wallet are available for immediate use, except for BART High-Value Discount tickets; these are available by the following day. Transit services Clipper is currently accepted on 24 Bay Area transit services: AC Transit Bay Area Rapid Transit (BART) Caltrain County Connection Dumbarton Express FAST Golden Gate Bridge, Highway and Transportation District Golden Gate Transit Golden Gate Ferry Marin Transit Petaluma Transit SamTrans San Francisco Municipal Railway (Muni) Santa Clara Valley Transportation Authority (VTA) Santa Rosa CityBus San Francisco Bay Ferry SolTrans (including SolanoExpress) Sonoma County Transit Sonoma–Marin Area Rail Transit (SMART) Tri-Delta Transit Union City Transit Vacaville City Coach VINE WestCAT Wheels A number of smaller regional transit agencies have not yet joined Clipper, including ACE and Rio Vista Delta Breeze. Clipper is not accepted on Amtrak California's Capitol Corridor or San Joaquins trains, despite these serving the Bay Area. Differences between transit services The fare rules for each participating transit service are set by the agency operating the service, not by Clipper. Each service has differing rules that approximate the fare collection rules used by that service prior to Clipper adoption, and are adapted to the needs of that service. For example, Golden Gate Transit uses