Bent Up Cycles - SRAM etap blip box. Technically, you only need this and don't need the blips. But I have found that shifting with the blips by the brake levers works
SRAM eTap® AXS™ BlipBox - YouTube
SRAM RED FORCE eTap AXS TT BlipBox 12S - AliExpress
eTap Blips | ES-EAC-BLIP-A1 | SRAM
SRAM Axs Etap Blipbox D1 Tt Aero 11 Speed 12 Speed Red Force Distributor - New | eBay
SRAM RED eTap BlipBox - Steiner's Sports Ski and Bike Albany, Glenmont, Valatie, Hudson