I'm sure there are threads about this but I couldn't find any so feel free to move me administrators!

My 4mth old Teagan has learned to roll-YAY! BUT....she has found that she is more comfortable to sleep like her Dad on her tummy. It is very cute but over the last 3 nights I haven't slept properly. I try and put her on her back once she is asleep but always manages to roll back on her tummy.
I've seen those things that you can put them in to prevent rolling. Are they safe according to SIDS? Do I leave her and she will be fine? What has everyone else done?