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: Professional Darts Steel Tip Set – Throwing Darts with Adjustable Length - 6 Brass Barrels 20 Grams + 12 Aluminum Shafts 2 Sizes + 12 Pro Flights + Dart Sharpener with GlFT Accessories Case
Product description: Rayna Games’ Team of product engineers with the advice from professional darts players created the 2019 Darts Steel Tip Set for anyone who wants to quickly improve their throwing accuracy while feeling confident like a pro.
Product feature: PROFESSIONAL DARTS STEEL TIP SET & DART ACCESSORIES KIT 6 Brass Barrels 12 Shafts 12 Flights 12 Rubber O-Rings Dart Sharpener eBook Premium Case, WHILE OTHER STEEL DARTS are wobbly and not straight, fall from the dart board very easily or their flights arent sturdy enough, the Rayna Games Steel Tip Darts have been designed with help from PROFESSIONAL players to ensure that every dart is TRUE and straight for 100% precision. The SHARP tip makes it EASY for you to always land your throw on the board and REDUCE bounce-outs while the pro flights INCREASE your accuracy by keeping the dart flat. PRIORITIES FIRST, MAKE EACH GAME YOUR MASTERPIECE You want to IMPROVE your darts control, BUILD the dart length that works for you or FEEL like a pro when you are playing your friends. We designed the MOST EFFICIENT darts steel tip set for your needs. Imagine holding a steel dart which feels just RIGHT (20 grams the go-to for most players), with a nice BURLING on the brass barrel to ENHANCE the grip and a STURDY flight thats what we call unstoppable. ITS NEVER BEEN EASIER, CONFIDENCE BREEDS PROGRESS & THATS OUR MISSION We are a family-owned business based in Maryland and we use our darts products every day. Thats why we asked for a PROFESSIONALs advice in building 100% BALANCED darts which can be adjusted depending on the players comfort zone by using the 2 SIZE SHAFTS included 6x35mm & 6x48mm. Control every throw with the PRECISION & STABILITY given by the SYMMETRIC design and CENTRALIZING fins. - JUST TAKE ADVANTAGE OF ITI, A MEMORABLE GIFT FOR A LOVED ONE - If you are looking for a great gift that has that INNOVATIVE extra-cool factor, then you would love our Limited-Edition Throwing Steel Tip Darts. The set includes 6 unbreakable BRASS barrels + 12 ROBUST shafts in 2 sizes + 12 SLEEK replacement flights + 12 O rings to ensure that your darts are ALWAYS tighten. We added a Dart Sharpener + Accessory Case to make it an INDESPENSABLE kit for any darts player (adult or kid) who shows up to perform. MAKE SOMEONE HAPPY, YOU DESERVE ONLY THE BEST QUALITYWe pride ourselves on providing only TESTED & PREMIUM products with LIFETIME Warranty and amazing UNITED STATES based customer support for our community of American darts fans. We designed the 2019 Professional Steel Tip Darts Set with ATTENTION-TO-DETAIL for the MOST EFFICIENT performance and QUICKEST improvement. Add the Hammerhead Steel Tip Darts to cart and if you arent 110% happy, well provide you with a FULL Refund.
Product price: $23.97
Product brand: Rayna Games
Target attributes: Weight
Answer: attribute: weight
value: 20 grams
source: product title
attribute: weight
value: 20 grams
source: product feature