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: MTX 12" Single 2 OHM Subwoofer 200W RMS
Product description: MTX Terminator subwoofers sound as good as they look. Classic MTX subwoofer cosmetics complement this subwoofer that is loaded with engineering technology including Spider Plateau Venting and Asymmetrical Linear Drive System which allow this subwoofer to be loud and play long. If you are looking for a great subwoofer that won't break your bank look no further.
Product feature: ALDS Asymmetrical Linear Drive System with a flat progressive spider and extended pole piece for smooth, linear, piston like drive, Exclusive Spider Plateau Venting cooling system cools at the voice coil, Rubber surround for greater durability and longetivity of the sub, 28 oz. Magnet structure, MTX Audio logo on dust cap
Product price: $7.43
Product brand: MTX
Target attributes: RMS Power Rating
Answer: attribute: rms power rating
value: 200w rms
source: product title