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: Syka Mens Retro Polarized Sunglasses Round Vintage Glasses Eyewear
Product description: Our Customers are telling us these are the most comfortable glasses they have ever worn. The Super light TR90 frame and lens only weighs .60 ounce. You can hardly feel them on your face, yet they are Unbreakable! TR90 Memory Frame for the most comfortable fit available today in addition to unparalleled durability. Great Fashion Frame Rimless design for Golf, Cycling, Running, Fishing and all Active Outdoor lifestyles. 100% UV protection lens. The fit is so pure, it is almost like you are not wearing anything!
Product feature: Al-Mg frame, TAC lens, polarized, Lens width: 53 millimeters, Lens height: 48 millimeters, Bridge: 16 millimeters, Arm: 132 millimeters, TAC POLARIZED LENS- 100% UV400 protection coating, blocks 100% harmful UVA & UVB Rays. Restore true color, eliminate reflected light and scattered light and protect eyes perfectly. TAC lens includes 7 layers. The 1st layer is polarization layer. The 2nd and 3rd layers are adhesive layers to enable durability. The 4th and 5th layers are UV protection layers to absorb UV light. The 6th and 7th layers are shatterproof layers., SUPERLIGHT, STYLISH, DURABLE- Lightweight design is ideal for usage by motorcycle and cycling bicycle, driving, running, fishing, racing, skiing, climbing, trekking or other outdoor activities enthusiasts. Fashion and stylish design, with rich color combinations of frames and lens. Polycarbonate lens and frames are impact, scratch resistant, durable and unbreakable., LIFETIME BREAKAGE WARRANTY ON FRAME & LENS - Frames and lens are unbreakable for no risk purchasing. In case any broken problem happens, contact the seller of Syka without hesitation to solve the problem until satisfaction. Syka provides lifetime after sale service for all Syka products., ULTRA LIGHTWEIGHT As with any piece of high-performance equipment, weight is an important factor. TR90 is incredibly lightweight, which contributes to the comfort of our eyewear and the tendency to forget you are wearing it., 30 DAY MONEY BACK GUARANTEE--100% satisfaction guaranteed. We are not only selling sunglasses but also providing excellent customer service. We promise if you are not happy with DUCO glasses within the first 30 days, we will refund you without any reason and take care of the returning shipping fee. SO NO RISK ON TRY!, Package Dimensions: 6.4 x 3 x 2.4 inches, Shipping Weight: 2.4 ounces, ASIN: B01EA45ET8, Date first listed on Amazon: April 15, 2016, Average Customer Review: 5.0 out of 5 stars 2 customer reviews
Product brand: Syka
Target attributes: Silhouette
Answer: attribute: silhouette
value: round
source: product title