The Acorn Chinchilla Mule slipper has a weatherproof synthetic sole equipped with a non-slip tread for secure footing, indoors or out.Treat yourself to the instant reward of the Acorn Chinchilla Mule.Vibrant.Easy tracking.. This cozy women's slipper has an easy-care, fleecy or wool-blend fabric upper and faux chinchilla fur lining and collar for superior warmth and luscious softness. Acorn's Signature Comfort Insole provides plush cushioning, and the memory foam over EVA midsole with a raised heel and arch deliver shock absorption and support