When sourcing rubber slippers, the primary material choice is between Natural Rubber (NR) and Synthetic Rubber (SBR/EVA blends). Natural rubber offers superior elasticity, slip resistance, and environmental friendliness, making it ideal for high-end eco-conscious brands. For mass-market retail, EVA-rubber blends are preferred due to their lightweight properties and cost-effectiveness. Ensure the material density is optimized for shock absorption and that the outsole hardness (Shore A scale) is between 40-55 to balance comfort and durability.