Instruction: Using the product's title, description, features, price, and brand, identify and retrieve the values associated with a specified set of target attributes. Output the extracted values along with their respective sources (e.g., title or feature) indicating where each value was found.

Input:
Product title: Rockford Fosgate R2D4-12 Prime R2 DVC 4 Ohm 12-Inch 250 Watts RMS 500 Watts Peak Subwoofer
Product description: Prime R2 dvc 4 ohm 12-inch 250 Watts RMS 500 Watts peak subwoofer features 2 inch copper clad aluminum voice coil stamp cast frame structure integrated PVC trim ring, Car Audio Fanatics who want Rockford Fosgate quality on a budget can rely on the Prime Series 12-inch subwoofers to get the job done, complete with a Dual Voice Coil for installation flexibility. These drivers can pump out the bass due to their mica injected polypropylene cone, and their stamp-cast baskets with spider venting--typically reserved for more expensive models--keep the motor running cool! These R2 subwoofers are optimized for sealed and vented enclosures., Rockford Fosgate pulled DNA from its big brothers to create the Prime series woofers. Parabolic cone designs result in solid bass reproduction and aluminum voice coils keep woofers running cool, even under demanding conditions. Straightforward mechanical designs mean you'll have solid performance for years to come. Add Prime woofers to any system and you'll "feel" the music you've been missing., Two things generally happen when voice coils heat-up too much: they can generate heat close to the melt-down temp of their adhesive bonds, leading to eventual failure, or the voice coil DC resistance increases, thereby reducing SPL output., Rockford Fosgate subwoofers use anodized aluminum voice coil formers that provide superior heat dissipation (up to 100 degrees at full power levels). Unlike traditional plastic substitutions, aluminum acts like a heat-sink to quickly dissipate thermal build-up on the voice coil. This keeps subwoofers cool during high SPL conditions., Power handling on Rockford Fosgate speakers conform to CEA-2031 industry standards. This means your speaker has the capacity to handle power under continuous damand, not instantaneous power handling, that over time, can damage voice coils., Multipoint "periodic" stitched lead wire technique reduces the mass of each tinsel lead and spreads stress and strain over a greater area, significantly improving the reliability and performance of the subwoofer., These stitched tinsel leads withstand extreme duty cycles, fatigue and high current that is critical to robust design., Setting the standard for excellence in the audio industry, the Rockford Corporation markets and distributes high-performance audio systems for the mobile audio aftermarket and OEM market. Headquartered in Tempe, Ariz., Rockford Corporation is a publicly traded company and manufactures its products under four brands: Rockford Fosgate, Rockford Acoustic Design, Lightning Audio and InstallEdge.com., Size: 12 Inches Impedance: Dual 4-Ohm Power Handling: 250 Watts RMS 500 Watts Max Voice Coil Diameter: 2 Inches Speaker Connector: Dual 12 AWG compression SPL(1w/1m): 87 dB Woofer Displacement: 0.150" Cutout Diameter: 11.22 inches Mounting Depth: 5.10 inches What's in the Box, Rockford Fosgate Prime R2D4-12 12-Inch DVC Subwoofer (Dual 4 Ohm), Documentation
Product feature: Features 2 inch copper clad aluminum voice coil, Stamp cast frame structure, Integrated PVC trim ring, 12-inch, dual 4-ohm subwoofer with 500 watts maximum power handling (250 watts RMS), Mica injected polypropylene cone with poly-foam surround, Linear spider with embedded 16 AWG tinsel leads, StampCast basket with integrated spider venting, One-year limited manufacturer's warranty
Product price: $7.43
Product brand: Rockford Fosgate
Target attributes: Impedance
Answer: attribute: impedance
value: 4-ohm
source: product description
attribute: impedance
value: 4-ohm
source: product feature
attribute: impedance
value: 4 ohm
source: product title
attribute: impedance
value: 4 ohm
source: product description