De or het glassponning?

The correct Dutch article is:

de glassponning

Rule Words ending in -ing: almost always de. See the rule

How to use glassponning

the glassponningde glassponning
this glassponningdeze glassponning
that glassponningdie glassponning
our glassponningonze glassponning
your glassponningjouw glassponning
every glassponningelke glassponning
which glassponning?welke glassponning?
a big glassponning / the big glassponningeen grote glassponning, de grote glassponning