LO does fine in a regular sleep sack at night in her RNP, but we are trying to transition her to the crib for naps. She doesn't like to be swaddled, but her arms flail around in the crib. Like many of you, I've been trying to get a zipadee zip but haven't had any luck. Today I had the idea to sew the armholes of one of her sleep sacks together and it seems to help. Plus, I didn't have to spend the extra money on another baby product. She gets some resistance without being completely confined. If you don't sew, you could always iron the holes together with stitch witch.