will these fit in my 2x4 wall??

i'm trying to install a recessed soap niche and was wondering if this will fit?

http://www.flooringsupplyshop.com/s...ed-ready-to-tile-combo-narrow-recess-462.html


my 2x4s measure 3 1/4 across and it seems like there isn't any recessed niches that fits my bill.




the recess linked is a 3.5 depth according to this chart.


thanks.