De or het dekmatras?

The correct Dutch article is:

het dekmatras

This word is not in the word lists we use to double-check answers.

How to use dekmatras

the dekmatrashet dekmatras
this dekmatrasdit dekmatras
that dekmatrasdat dekmatras
our dekmatrasons dekmatras
your dekmatrasjouw dekmatras
every dekmatraselk dekmatras
which dekmatras?welk dekmatras?
a big dekmatras / the big dekmatraseen groot dekmatras, het grote dekmatras