These were some of the iterations that were made. The decision to create a asymmetrical barrel created ease for doctors to manage the tool without needing to see their hand.  

The rendered product. Lagoa

Exploded diagram of the 3D printable and injection-moldable no-undercut product. The inventor concepted a 3-in-1 needle which had at the time not existed in the market but was conceptually possible. This prototype was a proof-of-concept for the inventor, who took the 3D files for prototyping and injection molding manufacturing.

These are the types of initial drawings given for the creation of the device. Specific tolerances were fleshed out later in the product development process