It's great to have spares of the silicone sock. I tend to print very high temp filements so the stock silicone sock degrades and become brittle quickly. Having these replacements at hand saves the day.
Sergio Gijón Iglesias
H2 v2.0 Original Heating Block/Silicone Sock
Would be nice to have the option to buy the silicon tubing with it too. A standard quick connector for the PTFE tube would be nice too.