Love, Love, Love this planter. 
We had a pre-wedding party for my son and his fiancee who loves sunflowers.  I arranged this on my mantle with lovely sunflowers(cut to just come above the rim ) in water and a little greenery. The flowers filled the narrow planter beautifully and I didn't even need foam or anything else to anchor them in. 
Looks absolutely lovely and very contemporary. I got the 32x3x3.5 size and it fits my mantle to a T. 
There are just so many things one could do with this. Last week I replaced the sunflowers with tealight candles on a bed of coffee beans and placed it in middle of my long dining table....... the coffee beans had the most lovely aroma at night during dinner when the candles were lit.
One could essentially change up the contents of this planter weekly, monthly or seasonally ....... myriad of possibilities.