Digimartz is official reseller for where to buy original Xecuter SX Pro and SX OS

SX Pro is the easy-to-use dongle and tool for booting SX OS on your Nintendo Switch.
SX OS is the revolutionary Custom Firmware for Nintendo Switch.
Advanced users can purchase this software separately.

Xecuter SX Pro and SX OS is in hot pre-order since announcced, Digimartz.com is the reliable official reseller as the screenshot shows:
digimartzDigimartz can ship over the world with free shipping 10-30 days, accepting Paypal and Western Union payment at your convenience. SX Pro and SX OS lovers could order any time.
SX Pro and SX OS Basic Usage “5 steps”
1. Extract SX OS to your Nintendo Switch’ microSD card.
Your card microSD can be formatted as FAT32 or exFAT
2. Insert SX Pro dongle and tool into your Nintendo Switch.
The dongle goes in the charger port, the tool in the right joycon rail.
3. Hold volume-up and press the power button, SX OS should start.
You can remove the dongle and tool once SX OS starts.
4. Activate your SX OS License to enjoy all features.
Enter the “album viewer” from the main menu and click on “license”
5. Enjoy the latest games and homebrew!