The Reflex skin is part of a Nvidia GeForce bundle. You will need to purchase a qualifying GeForce graphics card, laptop, or desktop to receive the Reflex outfit, Pivot Glider, Angular Axe, and Response Unit Back Bling. It is unclear how the Instinct skin will be released, it could be a different promotion or it might be an option you can get in the shop.
Here's the official information from Epic:
We’re excited to announce the GeForce Fortnite Bundle which is available for a limited time starting on November 29 and comes with the purchase of a qualifying GeForce GTX 1070 Ti, GTX 1070, or GTX 1060 graphics card, laptop, or desktop.
Enjoy the upcoming Season 7 with today’s available equivalent of our recommended graphics card, the GeForce GTX 1060, and a fantastic bundle to boot.
The GeForce Fortnite Bundle is packed with the following:
- 2,000 V-Bucks
- The Fortnite Counterattack Set, consisting of:
- “Reflex” Outfit (Rare)
- “Pivot” Glider (Rare)
- “Angular Axe” Pickaxe (Uncommon)
- “Response Unit” Back Bling
- Release Date: 11/29/2018
- Rarity: Rare
- Type: Outfit
- Availability: Promotion
Attachments are items that come with a cosmetic when a particular one is purchased.