⚠️ Starting January 1, 2027, older battery hardcase T21 transponders will no longer work on the 91 Express Lanes or other California toll roads, bridges, and express lanes. To see if you have a T21 transponder, please click here and then log into your account to check your transponder inventory. If a T21 transponder is listed, please call us at (800) 600-9191 for assistance.