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: Update International RS-SF/BK Black Sign Frame for Stanchion Belt
Product description: Update International Black Sign Frame for Retractable Stanchion BeltAdd a message to direct customers using this stanchion sign frame for Update International stanchion.Model #: RS-SF/BK Made for Update Intl. Stanchions 110639
Product feature: Made for Update Intl. Stanchions, Model #: RS-SF/BK
Product brand: Update International
Target attributes: Barrier Type
Answer: attribute: barrier type
value: stanchion
source: product description
attribute: barrier type
value: stanchions
source: product feature
attribute: barrier type
value: stanchion
source: product title
attribute: barrier type
value: stanchions
source: product description