I replaced mine with a standard (house) size, found out my walls wasn't set at 90 degrees so I gutted the hole thing, and glad I did. Now I can't stop, we did the Kitchen, Master Bath and sons bath now working on the livin room with a half wall and eat-at-bar. Pictured is my NEW Master bath which as a 5 foot by 5 foot walk-in shower.....Find that in a Mobile home on a lot.

take GOOD measurements and take those to lowes. They should be able to get you the right size