Merrell Lady Avian Light Convertible Sandals Cement Construction - Provides lightweight durability. Synthetic-leather upper - provides lightweight comfort and durability. Lycra neoprene lining - for padded comfort around your foot. Hook and Loop Closure System - Can be found on rearfoot, forefoot, and heel for quick adjustability. Dual density EVA anatomical footbed - Treated with Aegis antimicrobial solution, Protects against odour causing organisms keeping your feet cleaner and fresher.