O-rings provide reliable leak-free seals and simple installation. O-rings are an ideal, cost-effective solution for many sealing situations. An O-ring is a donut-shaped ring of molded, flexible material with a round cross-section that can be either solid or hollow. These flexible rings are designed to be inserted into a groove (referred to as a gland) where they predictably “de-form” themselves to completely fill the gap in the cavity, creating a perfect seal. Elegantly simple in function, the classic O-ring is the most popular choice for engineers as an ideal, cost-effective solution for a myriad of sealing challenges. Best used as a static seal, O-rings provide reliable, leak-free seals with ease of installation.