X1 carbon, 5th Gen. Managed to pick this up for £399 off eBay this week. i7 7600u, 16gb ram, 500gb SSD. Great condition. Only 175 battery cycles. Holds a good charge too. :
Lenovo ThinkPad X1 Carbon 2nd Gen i5 4300U 1.90GHz 4GB 256GB SSD 20A8 Non Touch | eBay