It’s a 2.5 gallon glass jar I found on Amazon. I’ve found similar sized ones at HomeGoods, but I like this one since the clarity of the glass was actually pretty good and didn’t have too much distortions like some of the other ones I’ve seen for sale.
Anchor Hocking 2.5 Gallon Montana Glass Jar with Fresh Seal Lid, Black Metal, Set of 1 https://www.amazon.com/dp/B000M9OQUE/ref=cm_sw_r_cp_api_i_7SOJEb1SHA7M4
Yup, fill them 3/4s full.