Indoor or Outdoor the Post-it Extreme Notes will hold up to the challenge! Created with ultra-strong Dura-Hold Paper and Adhesive, the Post –it Extreme Notes is water-resistant and durable while maintaining writable functionality. Sticks on tough-to-adhere and textured surfaces such as lumber, painted metal, steel, cement board, glass, and more! Extreme Notes even stand up to hot and cold environment and removes cleanly.