Oculus Rift S and the standalone Oculus Quest both begin shipping on May 21, Facebook announced during its F8 event on Tuesday. Pre-orders are now live for both pieces of virtual reality hardware, each of which sells for $399.

While both headsets use Oculus Insight, a suite of software that enables tracking of movement of the player and the controllers without the need for separate sensors and trackers, there are key differences between the two.

The Oculus Quest doesn’t require a connection to a computer, instead, it’s powered by a Qualcomm Snapdragon 835 chipset and 4GB of RAM.

The Quest comes in a 64GB version for $399 and a 128GB version for $499. The headset weighs slightly more than the Oculus S, at 571g and is slightly smaller. Both headsets support six degrees of freedom head and hand tracking. The Quest uses OLED display panels capable of displaying 1440×1600 per eye with a refresh rate of 72Hz. That’s a slightly lower refresh rate than the S, but better resolution.

The standalone headset is launching with support for 50 titles including the popular “Beat Saber” rhythm game and Turtle Rock Studios’ “Journey of the Gods.” The headset comes preloaded with demos for “Beat Saber,” “Creed,” “Journey of the Gods,” “Space Pirate Trainer,” and “Sports Scramble.”

Oculus is also selling a Quest Travel case that holds the headset, controllers, and charging cable, for $40.

The Rift S, which has to be plugged into a computer, is the upgraded version of the Oculus Rift, featuring improved optics and a higher resolution display.

The S headset weighs 563g, up from the 470g of the original Oculus Rift. It supports six degrees of freedom head and hand tracking, which means users will no longer need to use the sensors that came with the original model. It also means that tracking won’t be lost if a player turns their back to a sensor, because it’s built into the headset. The S uses a single fast-switch LCD panel compared to the OLED panels found in the original Oculus. The new panel features a resolution of  2560×1440 total compared to the original Rift’s resolution of 2160X1200 total. The S’s refresh rate drops to 80hz, down from 90h for the original.

The S also has a redesigned headset and slightly longer cable — 5 meters — for connecting to a computer.

Oculus announced the S in March during the Game Developers Conference. At the time, vice president in charge of content at Oculus Jason Rubin, explained to Variety why the headset wasn’t called the Oculus Rift 2 and discussed the impetus of some of the headset’s design changes.

Last month, ILMxLAB and Oculus announced that “Vader Immortal: A Star Wars VR Series” was coming to the Oculus Rift and Quest headsets this spring. They also gave attending press a chance to strap on a headset and dive into the virtual world.

The full list of Oculus Quest launch games and apps is below. The Oculus Rift S will run all Rift games.

1. Angry Birds VR: Isle of Pigs, Resolution Games
2. Apex Construct, Fast Travel Games
3. Apollo 11, Immersive VR Education
4. Bait!, Resolution Games
5. Ballista, High Voltage Software
6. Beat Saber, Beat Games
7. Bigscreen Beta, Bigscreen VR
8. Bogo, Oculus
9. Bonfire, Baobab
10. Box VR, Fit XR
11. Creed, Survios
12. Dance Central, Harmonix
13. Dead and Buried 2, Oculus Studios
14. Drop Dead: Duel Strike, Pixel Toys
15. Electronauts, Survios
16. Epic Roller Coasters, B4T Games
17. Face Your Fears 2, Turtle Rock Studios
18. First Contact, Oculus
19. Fruit Ninja VR, Halfbrick
20. Guided Tai Chi, Cubicle Ninjas
21. I Expect You To Die, Schell Games
22. Job Simulator, Owlchemy Labs,
23. Journey of the Gods, Turtle Rock Studios
24. Keep Talking And Nobody Explodes, Steel Crate Games
25. Moss, Polyarc
26. National Geographic VR Explore, Force Field VR
27. Nature Treks, Greener Games
28. Ocean Rift, Dr. Llyr Ap Cenydd
29. Oculus Browser, Oculus
30. Oculus Gallery, Oculus
31. Oculus TV, Oculus
32. Oculus Video, Oculus
33. Orbus VR, Orbus Online
34. PokerStars VR, LuckyVR
35. Racket Fury: Table Tennis, Pixel Edge Games
36. Rec Room, Against Gravity
37. Robo Recall, Drifter Entertainment
38. RUSH, Binary Mill
39. Shadow Point, Coatsink
40. Skybox VR Video Player, Source Technology Inc
41. Space Pirate Trainer, I-Illusions
42. Sports Scramble, Armature Studios
44. The Exorcist: Legion VR, Developer Wolf & Wood, Publisher Fun Train
45. Thumper, Drool
46. Tilt Brush, Google
47. Ultrawings, Bit Planet Games
48. Vader Immortal, ILMxLab
49. Virtual Desktop, Virtual Desktop, Inc.
50. Virtual Virtual Reality, Tender Claws
51. VR Karts, Viewpoint Games
52. VRChat, VRChat
53. Wander, Parkline Interactive