UGG Australia Womens Rella Boot nubuck Heel measures approximately 4.5 inches" Nubuck or leather and nubuck upper Insole: 7mm UGGpure sockliner that naturally wicks away moisture. Outsole: Lightweight and flexible molded EVA with cork and patent protected outsole tread design. 7mm curly UGGpure lining 4 1/2" shaft height