Instruction: Using the product's title, description, features, price, and brand, identify and retrieve the values associated with a specified set of target attributes. Output the extracted values along with their respective sources (e.g., title or feature) indicating where each value was found.

Input:
Product title: Mountaintop 40l Outdoor Sport Lightweight Backpack Mountaineering Bag Waterproof Daypack for Hiking Climbing Camping
Product description: Product Instructions: 1. Moutaintop 40L internal frame backpack 2. Water-repellent nylon fabric, SBS zipper, YNS brand fastener, reflective stripe, wateroutlet. 3. Tear resistant, wear resistant, powerful plug-in system, can hang sleeping bags,tents, walking sticks and all other things in all on this bag. 4. Waist width is about 120cm, you can Adjust the tightness as you need. 5. Colors: Blue, Green, Orange, Sky Blue, Yellow, Pink,etc About returns policy and our services 1. Please sending message, if you are not satisfied with our product or have ordered a wrong, we will reply you within 12 hours. 2. Please leave us your valuable feedback or product review with 5-stars, If you are satisfied with our products. 3. Please contact us first about your problem before you leave a negative feedback, and we will resolve it in a best way.
Product feature: Large capacity of 40L,breathable S-type strap,mesk belt,3D carrying system, Large front pocket, multiple zippered side pockets, and multiple elastic bands, inside the bag, ther is a laptop compartment, Two different fabrics: Quality polyester fabric; Water repellent, Tear resistant, Wear resistant,Breathable and moistureproof, Smooth and Comfortable, SBS zipper, YNS buckle-Cold-resistant and Securely; Reflective strip design, higher safety factor for night; Water outlet design, more humane, more convenient for travelling, Size: 55cm(H)x35cm(L)*25cm(W)
Product brand: Duhud
Target attributes: Material
Answer: attribute: material
value: nylon
source: product description