Best choices:
1. Steam tables or food warmers. If you need to cook a large piece of meat, a 1200 watt steam table is a good choice.
2. Traditional style commercial rice cooker with mechanical switch.
3. Slow cooker and home rice cooker.
Devices that also work:
1. Stainless steel commercial rice cooker with mechanical switch.
2. Tabletop Roaster
3. Rice warmer.
Devices that are not recommended:
Hot plate or Cook top.
Devices can't be used:
Electronics controlled rice cooker and slow cooker.
Detailed info:
https://www.auberins.com/images/Manual/Sous%20Vide%20application%20note.pdf
Recommended PID settings for WS-1500ES:
P=100
I=800
D=13