I can't get your link to work, but if it's what I think it is - a band of material to wear over your bump so you can still wear normal tops - then Ihave one and it's great. I'm thinking I should get another one.
I got mine off amazon and seems to be made of bamboo fabric so v v v v vsoft and comfy.
This is baby no3 and I wosh I'd had it for the others - would have saved me a fortune, especially as the shops are full of non maternity smocky things which fit very nicely over the top.