Definitely do bring a mask and glasses. The volcanic acid is no joke. Everything else would be provided by the company. They usually have camels to carry your stuff as well. Check out a group called Ethio Hiking Community on Telegram. They go roughly once a month.
Masks and glasses!!?? Went there, and such gear feels like it would be not only completely useless but even plain dangerous as it would probably contribute to make your body overheat even faster.