This is my epidura top tube bag from their racing line I’ve used this on almost every ride for a year and logged thousands of miles with it it comes in one half and one liter sizes and costs 60 to 65 dollars respectively it’s made out of a sturdy material epidural called
Hexalon and attaches to the bike with a strap on the top tube here and one around the headset here the epidural top tube bag has enough room to store in it a CO2 cartridge with a nozzle a hand pump Tire levers chapstick patch kit plug kit spare tube and a multi-tool
The only complaint I have is that sometimes the magnetic clasp will pop open when you hit a heavy bump or go over a rough gravel section you may also find that it occasionally tilts side to side while riding overall I found this a very convenient and accessible storage solution for my bike