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: Is this ac/dc power source?
Document: we have about 12 of them at any given time and we are not kind to them. they still can last a couple of years.
You will not be disappointed with a Metabo Grinder. I have been a hobby machinist/fabricator for several years and used my fair share of other big name grinders. All eventually let me down. After researching and hearing about Metabo, I decided to try them out. I bought one and liked it so much I am ordering a second!Easily the highest quality grinder I have worked with over the years and I expect it to last for years to come.
The housing is a bit more bulky than most comparable 4-1/2&#34; angle grinders, but the Metabo runs smooth with less vibration. I use mine with cut-off disc, flap disc, and grinder for pipe welding. This is the model without the deadman switch, which I prefer since I use it mostly without the side handle. If you're always going to be using the side handle, a deadman switch is safer and more convenient.
I've been using this grinder to cut, grind, and sand sheet metal while I restore my Blazer. It is an absolute beast. I have gotten the cutting wheel caught twice but the clutch disconnects and the motorr was completely okay. After looking around for several weeks to find an American made grinder I was disapointed to see that all of the grinders on the market are made overseas. Not wanting to support the Chinese I decided on the Metabo. German manufacturing is certainly on par with America.
I was taking a welding class at a local community college and I needed a grinder. i checked what other guys had, checked online, and decided on the Metabo. I am so glad I did, it works flawlessly and is powerful. It has exceeded my expectations.
I needed a new grinder to replace my 17 year old Porter Cable Grinder and this wasrecommended by several people as the best even tho it isn't made in the USA which I was looking for. I haven't used it much yet but so far it has performed well. I like the "no wrench changing of the disc.
I am the type of guy that will wait till I can afford to buy a quality tool before I go cheap in most cases! This grinder burns stuff up! Very smooth and the lack of a paddle switch seals the deal!
Didn't think I would like an angle grinder so much, but I do. I'm cutting hardened steel chains and the Metabo slices them like a hot knife through butter. When I screw up and bind the disk in the cut, the clutch kicks in and prevents damage. The quick change mechanism works every time and is easy to use. I fully expect to use this sturdy machine the rest of my life, so I don't expect to buy another one. But if I do, chances are it'll be another Metabo.
By far the best product one could buy for grinding and cutting. This is actually the second Metabo unit. I was expecting a half as good a product compared to my first unit. This is double the product of my 7 year old grinder. I have pressed both units into a manufacturing process and expect both to last many years to come......
After purchasing a couple of other grinders and having failures I decided to &#34;bite the bullet&#34;.So far the Metabo has done the job. I used Metabo grinders at my job so I should have just went with one for my personal use..DOH! !The quick change is nice. No tools for disc swap or adjusting guard.
Answer: no