This is the rectangular puff I am currently using.

Among the Jeffuff Turtool Lab Hydro Makeup Sponges

It is a rectangular type being used over a large area.

It is different from a regular makeup sponge.

Made of high-elasticity, high-density material, it feels bouncy even in your hands. It absorbs and releases water quickly; since sponges typically absorb a lot of foundation and require you to squeeze out more than with a puff, you don't need to do that with this one. If you use it slightly dampened with water, you can also achieve a dewy glow effect. The grip is also great, and the best part is that it is wide, allowing you to quickly and thoroughly fill in any gaps.