The AirPods will come with either the standard case or the new wireless charging case. Both will still hold a top-up charge for "more than 24 hours of total listening time" and the wireless case is Qi-compatible for any chargers you're already using with your new(ish) iPhone.
The new headphones have a new Apple-designed H1 chip, developed for headphones, and aimed at faster connect times, better battery life and, yes, hands-free "Hey Siri" too. Your new wireless headphones will always be listening for your audio commands. That new chip apparently promises improved synchronization as well as two-times faster switching between your iOS devices and the Apple Watch.
The wireless charging case option will be available for $199 (or £199) and are available to order on Apple's retail site and the Apple Store app starting today. For old-school charging only, the price is $159 (£159)-- same as the original model. And if you just want the case to upgrade your existing AirPods, then that will cost you $79 (£79) -- arguably not too aggressive a price for the standout feature of AirPods Generation 2. Also new for 2019, AirPod buyers can add a personal engraving to the headphones free of charge.