Curved Tweezer
Straight Tweezer
 
These are precision hand tools designed with the lash artist in mind.  The Curved tweezer is ergonomic designed to allow for enhanced maneuverability and precise control when gripping and manipulating, and isolating the lashes. The Straight tweezer is ideal for grabing the eyelash extensions from their strip for a precise grip and hold.  
So many artists use these interchangably, however best they are for you.
Their versatility makes them a valuable tool for professionals, providing a comfortable and efficient solution for various intricate lash techniques.