Search engines truncate the display of descriptions when they are too long so do a search on the engine you are aiming at, check out the length of description that they are displaying and write yours to fit. It is better to have a complete description on display that to have it stop suddenly in mid sentence. I like to keep my description tags to about 25-30 words. I try to lead off the description with my most important keyword and then try to repeat the same keyword twice more. You may consider putting both singular and plural versions of the keyword in the description.
Some engines recognize both, and some are sensitive to which is searched for.
When writing the description, remember that anything meant to mislead the surfer to places that they did not want to go is considered Spam and highly frowned upon by this association and all the major search engines. Misleading and irrelevant descriptions are considered to be spam. It's effect is to automatically load the next page in the number of seconds specified. The example would fetch the next page in 0 seconds. It is sometimes used unscrupulously to redirect surfers to sites and pages that they didn't choose to go to.