The safeTsleep is great for wriggly babies. It helped keep my eldest in her cot when I had to elevate the head for her reflux. My second child bumped into the edges of the cot and the safeTsleep stopped her waking herself up. I love that it can be used on adult sized beds with the extension too when we go away and no cot is available. The addition of the bit between the legs was genius too.