My almost 3 year old only wants to be carried in ring slings. So my most impt criteria for rs is that it must be comfy for one shoulder carry of this almost 14kg boy. I've tried various ring slings with linen, hemp etc & so far I've found flax to be the most supportive & comfortable. It's also thin & airy enough cos my boy sweats really easily. Plus it folds up small which is great cos he doesn't always want to be carried & I don't want to lug along too much bulky stuff. And it was soft right from the start, no breaking in needed! So soft, that my elder kid love to snuggle with it as in the photo!