Definitely find out if the unit you're going to is one that issues each baby their own 'scope, or you use your own.
If you're using your own, start w/an infant size one. Littman is the best, of course, and there is only one model to pick from. Adscope makes an infant stethescope that is just fine, but cheaper.
I take care of a lot of squirmy newborns, and I have found lately that the pediatric size Littman (again, only one model) makes it easier for me to hear and count! So, that's my
If you already have one of those fancy Cardiology Littmans, why don't you use it for a while, see how things go, and what the other nurses are using, maybe try one of those out if they'll let you.