I was having issues after a descale, apparently this happens, I cleaned the original sensors and the steam wand would activate most of the time. So I figured I would just replace them. The O rings I purchased elsewhere seem to be too big and thin compared to the ones that came on this set and ECS told me they are OEM and new. So then I installed the new ones with the included O ring, put lube, and everything works super smooth! Very happy I could get my machine up and running with fast shipping and parts.