Question about Wilesco Steam engine D21

I can buy a steam engine for over CHF 400 on Digitec/Galaxus but not the necessary accessories such as Wilesco WiTabs and Wilesco steam engine oil Z83? Or am I too stupid not to find these two items? It is logical that these two items should always be available from stock, because you want to be able to operate your steam engine at any time. What else is needed? Should I use rainwater or distilled water? Article number for rainwater on Digitec/Galaxus? Okey, that was a joke! :)