Meta descriptions can be up to 160 characters long.
Meta descriptions should be written in a way to promote users to click on your content to read more or purchase products. Be aware as of September 2009 Google no longer uses meta descriptions in it ranking. This being said it up to you to write a 160 character description that will promote users to want to click and see more content of that page. There are a few things to remember for meta descriptions...
- Don't use double quotation marks. Search engines will cut off any content after the first quotation mark.
- Sometimes it's OK not to write a description. If the page requires many keywords to be found it might be best to let the search engine scrap the page on it own and create its own meta description.
- Sometimes search engine will not use your meta description. If the search engine doesn't think the description is fitting it will scrap it own description together for the page. My point to the fact you need to redo you own description of the page.