Is there a length limitation for each long tail keyword?

Is there a length limitation for a long tail keyword?
I choose a long tail keyword" Adidas Water Grip Surfing Shoes ".
But I can never find "Adidas Water Grip Surfing Shoes" on Google Webmaster Tool.
Instead,I only find "Adidas Water Grip","Adidas Water Grip Shoes","Water Grip Adidas","Adidas Water","Adidas Watergrip","Adidas Water Shoes" and "Shoes in Water" on Google Webmaster Tool.
It seems that there is a length limitation for a long tail keyword.
However,I can also find "mac studio fix powder plus foundation" on Google Webmaster Tool,which is longer than "Adidas Water Grip Surfing Shoes".
I am confused.
Please help me out with it.

Excerpts: What Exactly is a Long Tail Keyword? http://www.calculatemarketing.com/blog/discussion/what-exactly-is-a-long-tail-keyword/

Number of words in keyword

It makes sense that a long-tail keyword contains a greater number of words than a short-tail or head keywords. But exactly how many words should a long tail keyword contain?Although some definitions of long tail keywords specify a lower and upper limit for the number of words it must contain (e.g. 3-6 words), it makes little sense placing an upper limit on the maximum number of words a long-tail keyword can contain.The more important question here is exactly how many words should a keyword contain until it is classed as long tail? In the definitions we looked at earlier, we???ve had mentions of anything over 2 words, anything over 3 words, and anything over 5 words.

Then there is the question of whether the number of words in a keyword really matters at all. For example, a short keyword such as ???antique bingo clothing??? (3 words and very niche) might be considered long-tail, whereas a longer keyword such as ???car insurance for women??? (4 words and very popular) might be seen as highly competitive and therefore not a long tail keyword. So perhaps the number of words isn???t useful in defining long tail keywords. Perhaps search volume or competitiveness might be better.

No, there is no length limitation for long-tail keywords. What you see in Google keyword tools are the keywords that your target audience and competitors are targeting aggressively. You may target ???Adidas Water Grip Surfing Shoes??? but you must definitely optimize your website for all others that you mentioned because those must be highly competitive.

Yes. There is no restricted limitation on long tail keyword. In always depends on the volume as mentioned by the excerpt I stated above. It means that ADIDAS WATER GRIP SURFING SHOES is more competitive than the ADIDAS WATER GRIP when it comes to search engine.

Very well written summer..
I used to think that .. number of words in keywords matter the most .. but there are certain other factors,, which are responsible for determining a keyword long tail or normal generic keyword!!
What i personally experienced is keywords having more than 5 words are difficult to target .. coz the techniques which we ise to target keywords doesn't allow more than 5 keywords...
For ex... there are certain article submission sites .. which does not allow you to link more than 5 words together!!!

Plus the fact that there also existing keyword which would might be the same as yours. It puts a heck of competition on this when it comes to search engine.

Long tail keyword should include 3 or more words but I think it should not be more than 7-8 words.