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: SmartWool Women's NTS Mid 250 Crew Top
Product description: Our best selling, and warmest, baselayer, just got a little more refined with an improved fit, chafe-free seam construction and panels that offer more comfort with a pack.
Product feature: 100% Merino Wool, Made in USA or Imported, Machine Wash, 2" high, 9" wide, 100% Merino wool interlock knit provides ultimate comfort, Crew neck with set in sleeves, Back body seam wraps to front for body enhancing fit, Shoulder panels eliminate top shoulder seams, Flatlock seam construction is designed to eliminate chafing, Product Dimensions: 10 x 9 x 2 inches, Shipping Weight: 6.7 ounces ( View shipping rates and policies ), ASIN: B07HSB1PPQ, Item model number: SW-NP224-$P, Date first listed on Amazon: September 19, 2012, Average Customer Review: 4.3 out of 5 stars 22 customer reviews
Product price: $90.00 - $99.99
Product brand: SmartWool
Target attributes: Fastening Style
Answer: attribute: fastening style
value: None
source: None