Hi Luis, Hornady Black and Hornady Critical Defense buckshot are both 12 gauge 00 buckshot loads that appear to have similar construction and performance, using the same Versa-Tite wad design. However, they may differ in marketing and packaging, with some users suggesting they are essentially the same product under different branding.
They appear to be one and the same >>> https://civiliangunfighter.wordpress.com/2018/08/09/a-critical-look-at-some-hornady-buckshot/
Stay safe & have a great day!

What they are called.

The primary difference between Hornady Black and Critical Defense buckshot loads is the packaging and marketing, with the actual ammunition potentially being the same load with different markings. Both 12-gauge, 2.75" shells containing 8 pellets of 00 buckshot, with a listed velocity of 1600 fps, are essentially identical in terms of ballistics and performance. The Critical Defense line may feature a "Versatite Wad," which is designed to improve pattern consistency, but both loads are known for stout recoil.