What is the NGC Coin dealer locator?

Excuse me, could you please elaborate on what exactly the NGC Coin dealer locator is? I'm curious to know if it's a tool or a service that helps individuals find reputable and reliable dealers of NGC-certified coins. Additionally, I'm wondering if it's accessible to the general public and if there are any specific requirements or steps one needs to take in order to use it effectively. Lastly, I'm interested in knowing if the NGC Coin dealer locator covers a wide range of dealers or if it's limited to a select few. Thank you in advance for your assistance.