India recently announced that they’re on the market for 110 new fighter jets, and they’re willing to fork over more than $15 billion to get them. Naturally this has prompted a great deal of interest from aircraft manufacturers throughout the world. One such manufacturer, America’s Lockheed Martin, has approached the table with a “brand new” fighter they’ve dubbed the F-21, a platform they claim will help bridge the gap between fourth- and fifth-generation fighter platforms for India while serving as a stepping stone leading to new defense technologies in the future.

It may come as a surprise to many that Lockheed Martin, the same company responsible for producing both of the world’s premier fifth-generation platforms—the F-22 Raptor and F-35 Joint Strike Fighter—would be eagerly pushing a brand new fourth-generation platform. For most Americans, though, the F-21 will probably look awfully familiar—and not just because ATAC already produces an F-21 for U.S. service.

Lockheed Martin’s F-21 appears to be the next iteration of their Block 70 F-16, first unveiled in 2015. At the time, they pitched that platform to India and others as “the most advanced fourth-generation fighter on the planet” thanks to a wide array of updates and upgrades fitted throughout the aircraft, including upgraded avionics, radar, ground avoidance systems, and pilot interface.

Proposed F-21 (left) and U.S. Air Force F-16 (right)

Among the most prominent upgrades the Block 70 F-16 boasted was the addition of APG-83 AESA radar, which has the capability to track up to 20 different targets simultaneously and provides the pilot with a far more developed level of situational awareness than can be found in many more dated fourth-generation platforms. The F-21, which would boast the same systems, would leverage the Block 70’s data fusion capabilities in a way that approximates what we’ve come to expect from fifth-generation fighters like the F-35.