Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: Jack Wolfskin Board Walk 20 Backpack
Product description: Rucksack for kids aged ten and over.<br /><br /><br />The comfortable suspension system features shoulder straps with a wide contact surface for good weight distribution - all to make carrying those books easier. The contact surfaces on the back and shoulder straps are padded for comfort. <br /><br />The partitioning of compartments makes it easy to stay organized: there are two A4-sized compartments, one behind the other, as well as a large front pocket, a flat lid pocket and two side pockets for smaller items.
Product feature: 100% Polyester, Imported, Main compartment, five pockets, School rucksack, For children aged ten and over, Suspension system with wide straps, Suitable for holding A4 documents
Product brand: Jack Wolfskin
Target attributes: Material
Answer: attribute: material
value: None
source: None