Studies have shown that erection hardness is positively correlated with maintenance time, with the harder the harder the longer it lasts. Erection hardness is usually medically classified into 4 levels of hardness, with 4 levels of hardness like a gherkin representing the optimal hardness to be able to penetrate. The hardness of the erection and the maintenance of hardness are central to sexual life, and the more satisfying the erection, the more satisfying the sex life. In reality, not every man can achieve level 4 erection hardness, and men with erection hardness below level 3 should not be frustrated, as studies have shown that many oral medications are now available to help men achieve level 4 perfect erection hardness and maintain a full hard erection to help achieve a satisfactory sex life for both partners.