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: Ridgid 18v Impact Driver Rigid R842301
Product description: Features: * 18 Volt Impact Driver features high torque output for the toughest driving tasks * Die cast gear box--for durability and repeatability * 1/4 in. hex quick coupler--makles bit changes quick and easy Specifications: * Coupler: 1/4 in. hex quick coupler * No Load Speeds: 0-2400 r/min. * Torque: 1450 in.lb. * Impacts per Minute: 0-3,100 Additional product information: TOOL ONLY Battery and charger not included.
Product feature: 18 Volt Impact Driver features high torque output for the toughest driving tasks, Die cast gear box--for durability and repeatabilty, 1/4 in. hex quick coupler--makles bit changes quick and easy, TOOL ONLY, Battery and charger not included.
Product brand: Ridgid
Target attributes: Voltage
Answer: attribute: voltage
value: 18 volt
source: product feature
attribute: voltage
value: 18 volt
source: product description
attribute: voltage
value: 18v
source: product title