Twitter is teaming up with American Express to allow card members to purchase products via specific hashtags on the micro-blogging site.

American Express customers who sync their cards with Twitter and tweet special hashtags will be able to buy things via Amazon, Sony, Urban Zen, and Xbox 360, as well as AmEx gift cards.

To kick things off, card members will be able to buy a $25 American Express gift card for just $15 by tweeting #BuyAmexGiftCard25. There's a limit to one card per member, and the deal expires on March 3.

The other hashtag specials will go live on Feb. 13 at noon Eastern. That includes the Amazon Kindle Fire HD for $149.99, the Sony Action Cam & Waterproof headband mount for $179.99, the Urban Zen bracelet designed by Donna Karan for $80, an Xbox 360 4GB console with a three-month Xbox Live subscription and two-month tokens for $179.99, and an Xbox controller for $29.99.

The card sync feature first launched in March 2012. "Based on the initial success of Amex Sync for offers, we know there is significant power in combining our assets with Twitter's platform to bring value to Cardmembers and merchants," Leslie Berland, senior vice president of Digital Partnerships and Development at American Express, said in a statement. "Now, we're leveraging our unique technology and closed-loop network to introduce a seamless solution that redefines what's possible in the world of social commerce."

Those who have already synced their card with Twitter need to add a few more details in order to activate the new hashtag feature, including billing address for product shipments.

Once users tweets a particular hashtag to take advantage of a deal, the @AmexSync account will confirm via a reply tweet within 15 minutes. All products will ship via two-day free shipping.