Duplicate Mega tags

[DFC]

we have a e-commerce site, we have products that are the exact same but different sizes each has a page, we use the same mega tag would it be better to use no mega tag

[Unity]

First see if you can automate the meta descriptions so they are unique. So create a rule that changes one or two words. Easy to use terms for the rule would be things like product names, product models, product size, category names etc.

Or, if the pages are so much the same would canonical tags be possible? This will communicate to search engines which one page is the priority page. That way your duplicate or light content on other pages shouldn't cause any penalties.

[DFC]

I could add  the size in to the mega tag, would added 20 x 34 be enough to solve the problem?

[Unity]

It makes them unique yes but you might want to add a little more. If search engines don't think your meta tags are a true representation of the page or if they are duplicated across the site then the search engine will choose whatever content it wants, and often this isn't a compelling introduction to the website.

Private message me your URL if you like and I can have a look and see if there are any additional automation opportunities for your tags.