For a heading you can just use apparatus (but NOT apparatuses) or if you really want to have something in the plural you could say "types of apparatus" perhaps.

Strictly speaking, the correct plural of 'apparatus' is 'apparati' (i.e. the true latin plural), though this form is in my experience commonly not employed by the majority of native speakers within the English speaking world --- even in the scientific and engineering communities. Typically 'apparatuses' is used instead. Should you not feel comfortable with either option, you may choose an indirect description like the proposed 'types of apparatus', or '[different] kinds of apparatus' etc.

Da "apparatus" auch "Ausrüstung" bedeutet, worunter man ja auch mehrere Gerätschaften subsumieren kann, kannst Du m.E. "apparatus" als Überschrift wählen und dann die verwendeten Instrumente aufzählen.

So wie es im Deutschen auch oft "Material und Methoden" (und eben nicht "Materialien und Methoden") heißt.

For the record, apparatus is a fourth declension noun in Latin. The plural is appartus, with a long u, not apparati. The reason apparati isn't much used is that it doesn't exist.

I would call it "Instrumentation" or "Setup", which has a fresher ring to it.

Wiktionary says both are possible.
apparatus (plural apparatuses or apparatus)
http://en.wiktionary.org/wiki/apparatus#Noun

Thanks for that, mabr. "apparati" sounded odd to me too, but my school Latin doesn't equip me to know why. I thought "apparatus" was probably a past participle, so it's just as well I kept silent;-).

Also for the record, when writing up experiments in chemistry/physics, it's usual to use the heading Apparatus (singular) for the equipment used and Method, at least in school.

Actually, it's a fourth declension masculine noun in Latin , so the plural of "apparatus" is "apparatus" in the nominitive case, just as it is in English.

http://en.wiktionary.org/wiki/apparatus

Fourth declension (4).

Number Singular Plural
nominative apparātus apparātūs
genitive apparātūs apparātuum
dative apparātuī apparātibus
accusative apparātum apparātūs
ablative apparātū apparātibus
vocative apparātus apparātūs

Those pre-Vatican II masses were worth something.

In my experience, apparatus is usually used as if it were an uncountable noun, even if a plural technically exists. So to talk about more than one item, you would say "pieces of apparatus" or "items of apparatus", etc. For a heading, just use "Apparatus".