The jars are just wide mouth ball jars. The plastic ring and silicone bubblers were an Amazon purchase a while back. They come in small or wide mouth and are pretty cheap. Great for ferments because you avoid rusty stuck lids. Here’s a link:

https://www.amazon.com/Masontops-Tough-Bands-Rust-Proof-Reusable/dp/B075KN8B2K?th=1&psc=1