The reviewer, Ruth, discusses the cosmetic product "bye panda eyes! vol. def. masc. by .essence." in their video review. They mention that the mascara claims to be volumizing, defining, and smudge-proof. Ruth demonstrates the application process, showcasing the fluffy wand brush. They express surprise at the noticeable difference the mascara makes, emphasizing its effectiveness in adding volume and definition to the lashes. Overall, the product seems to deliver on its claims, providing impressive results. However, the review does not mention any potential drawbacks or limitations of the mascara.