Promaster 6543 39mm HGX Prime

The threading is so smooth, it screwed on without any resistance. Clear glass too, no weird color cast in my test shots.

Installed this on my 39mm lens and the threading is smooth as butter, no cross-threading worries. The glass is crystal clear, doesn't introduce any color cast.

I was worried about glare on my vintage lens, but this filter handles reflections beautifully without adding any noticeable color cast. The glass feels solid and the threading is smooth.