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: Hanes Mens 5-Pack Best Tagless Boxer Brief with Comfort Flex Waistband (Medium (32" - 34"), Black/Grey)
Product description: Get comfortable with the Hanes Men's Best Comfort and Fit Boxer Brief 5-Pack. An ideal everyday men's wardrobe basic, these classically styled tagless boxer briefs are made with preshrunk 100% ring spun cotton for a soft breathable fit wash after wash. They are equipped with a fabric covered ComfortFlex waistband that is both soft and stretchable and won't pinch or bind. These boxer briefs also feature no ride up legs and a standard front fly.
Product feature: 75% cotton, 25% polyester, Machine washable, TAGLESS - the ultimate comfort boxer brief that's itch-free with NO scratchy tags, STRETCHABLE - Plush, Comfort Flex waistband won't pinch or bind and is nice and stretchable, NO RIDE UP - contoured design is engineered to ensure that they will NOT ride or bunch up throughout the day, SUPER SOFT - 100% ring spin cotton feels smooth against the skin. Ring spun cotton is a premium knit that ensures that the fabric is more consistent. It's softer and more durable., BREATHABLE - lightweight design promotes air flow preventing you from getting hot, Package Dimensions: 10.3 x 8 x 3.8 inches, Shipping Weight: 14.7 ounces, ASIN: B010G6ML86, Item model number: SCB1B5, Date first listed on Amazon: June 26, 2015, Average Customer Review: 1.0 out of 5 stars 2 customer reviews
Target attributes: Silhouette
Answer: attribute: silhouette
value: boxer brief
source: product description
attribute: silhouette
value: boxer briefs
source: product description
attribute: silhouette
value: boxer brief
source: product title
attribute: silhouette
value: boxer brief
source: product feature