Microsoft is celebrating Pi Day for the fourth year in a row with discounts on laptops and Windows Mixed Reality headsets. Dell’s XPS 13, XPS 15, the Alienware 15, and a variety of older models from Dell, HP, Asus, and Lenovo are all discounted by up to 31.4 percent today. Microsoft is even offering laptops for $314 to mark Pi Day, including models from Asus, Dell, Lenovo, and HP.

The Microsoft Store also has discounts on the company’s Windows Mixed Reality (VR) headsets, with HP and Lenovo’s models both available for $314. This isn’t the first time we’ve seen Microsoft’s VR headsets discounted. In January all models from Dell, Acer, Lenovo, and HP were available for under $250. Microsoft also has a number of other non-3.14-related deals available, including discounts on the Surface Laptop and Xbox One games available in the Microsoft Store.