Amazon is currently running a special deal on a pair of Trico Force.
The offer is only available at Amazon and the blades must be sold and shipped by Amazon.com.
This means that products sold by 3rd party sellers unfortunately does not qualify for the discount.
Amazon has put together a special page where you can add your wipers directly to your shopping cart (the discount is applied in the shopping cart)
If you don’t know the exact size, then use the Part Finder (not the “normal” Part Finder) on the special offer page to make sure that 1) you select the correct blades and 2) that you only select from products included in the deal.