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: Danya B. WL4015B Floating Black Smoke Tempered Glass Display Shelves with Chrome Brackets (Set of 2)
Product description: Danya B. Pair of 16" Black Glass Floating Shelves with Chrome Brackets can add storage space and a modern look to any room at home or at the office. Each shelf comes with two chrome brackets that mount easily to the wall. Danya B. black glass shelves are made of strong tempered glass, also known as safety glass, and finished with highly polished edges
Product feature: Add storage space and a modern look to any room at home or at the office., Materials: Tempered Glass and Metal. Colors/finish: Black Glass / Chrome Brackets, Easy to install brackets in contemporary chrome finish, Made of smoke black tempered or safety glass with highly polished glass edges, Dimensions: 2 inches high x 16 inches wide x 6 inches deep each
Product brand: Danya B
Target attributes: Placement
Answer: attribute: placement
value: to the wall
source: product description
attribute: placement
value: floating shelves
source: product description