V5/V6/Volcano/SuperVolcano heat breaks
This article is a sum up about the best heat break options on the market to this date.
My personal opinion:
If you are OK with spending a few more buck, choose the best option on the market which is a copper + ceramic heat break.
If you want to buy a budget heat break, get a titanium one.
I strongly advice against the standard all metal heatbreak which causes a lot of problems such as clogging while printing PLA with retractions above 0.5 mm.
This is the newest heat break type of the best affordable materials. Inner tube from aerospace material - high temperature resistant ceramic ensures the best heat resistance between hot block and heasink. Copper on the other hand is a very good heat conductor and helps to transfer heat to heatsink.
Titanium used to be the best option. It is strong enough to support even SuperVolcano and it's heat conductivity is very low. However the heatsink does not work so efficiently due to the low temperature conductivity of titanium.
The idea behind this heat break design is the same as behind the copper and aerospace one. Copper on the hot side helps to keep the temperature high and melt zone with a higher volume and on the cold side helps with heat transfer from the heat break to the heatsink.
This is the most common heat break on the market. Most of the V5/V6 kits have this one inside. But be aware, this heat break causes a lot of problems with PLA. It's heat conductivity is relatively high and it leads to clogging due to the PLA's low melt temperature.