De or het diacassette?

The correct Dutch article is:

de diacassette

Rule Words ending in -te: usually de. See the rule

How to use diacassette

the diacassettede diacassette
this diacassettedeze diacassette
that diacassettedie diacassette
our diacassetteonze diacassette
your diacassettejouw diacassette
every diacassetteelke diacassette
which diacassette?welke diacassette?
a big diacassette / the big diacassetteeen grote diacassette, de grote diacassette