Instruction: Analyze a question and its supporting document. Predicting answerability based on the information provided in the document. Output yes if the document contains relevant information to answer the question, otherwise output no.

Input:
Question: If the upper section of the pole is detached from the middle setion, how is the upper section reatached to the middle section?
Document: When extending the poles, the lowest section has a small &#34;stop&#34; label, but it is just before you pull the section free of the upper part, which is easily done. It would have been nice if they had added some graduated markings that show you when you are nearing the stop point. Once extended and locked, however, the poles retain their length and strength very well.
We purchased 2 sets of these walking poles. Our feelings are mixed. Three out of the four poles were great, extending and collapsing properly, and providing good support. The upper section of the fourth one, however, refused to collapse after the first outdoor use. The mechanism just clicked back and forth, without engaging or disengaging. Couldn't shorten it, couldn't pull it apart to start over.
One of the two poles would not lock the upper portion in the open position. I am very disappointed with this product.The same day I posted this review BAFX contacted me by e-mail and offered to replace the defective pole. I declined the offer and they promptly refunded my money.
For the price I wasn't expecting much, but they are very nice poles. The second time I used them, the bottom section of one came out. While trying to put it back together it broke. Say want you want about following the instructions (which are clear only after you do what they tell you not to do), but it was 10F outside, I'm in deep snow, fumbling with a cold pole and trying to get it back together. For the casual user these will be great.
Also, whenever I moved the pole, something rattled inside one of the middle sections. I am returning these to Amazon, and investing $55-$60 extra to get trekking poles that are half the weight, with flip locks.For someone who wanted to do some local hikes (not an extended expedition) and just wanted a sturdy pair of walking sticks, these would be fine--provided the locking mechanisms weren't pesky. Maybe I got a dud.
Purchased for hiking Vernal Falls & Upper Yosemite Falls and loved them. Easy to change lengths and did not let me down. They helped me going up and coming down. No negtaive reviews on how they performed, though one of the compass fell out (which does not matter because this is not the reason why I purchased them). Overall two thumps up!
I bought two pairs of these last year for a trip to the grand canyon. They are amazing for the price. They extend all the way to my upper chest. Maybe ... 3.5 feet? They are sturdy and durable. They come with attachment for different kinds of terrain. For the price, these can't be beat.
I was a little bit hesitant to get these as the price was so low compared to other products. I decided to roll the dice and bought these. They arrived in perfect condition in an oversize box and very easy to assemble--or should I say extend. The locking plastic ring on each section turns easily, the poles slide out nicely with stop indicators.
I knew they were adjustable but didn't realize they had 2 sections that were adjustable, not 1. So, for the first few weeks I used them they seemed to be too short for me (I am 5'11) and I was somewhat disappointed. Then, I discovered that the lower section also can telescope out! Once that was adjusted and tightened it was perfect! I like the different kind of tips for various walking conditions.
I walk daily after suffering a stroke 2 years ago, I am weaker on one side and these give me the support I need without carrying a cane and looking like an old lady. I use them for hikes in the  woods and on concrete. Great for upper body exercise.
Answer: no