SRAM eTap Blip Box Bike Computer for sale online | eBay
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
Handmade Sram Etap Blips Axs Blips Buttons For Tt Bike Dust And Waterproof Blipbox Remote Controller For Red Axs Force Axs - Bicycle Derailleur - AliExpress
SRAM Red eTap Electric Aero Kit: 650mm Blips, Blip Box, Derailleurs, & Batteries - Walmart.com