Endpin stops are small devices used on string instruments, such as cellos and double basses, to prevent the endpin from slipping too far into the ground. The endpin is a metal or wooden rod that extends from the bottom of the instrument, providing stability and support while playing. These stops can be made from various materials, including rubber or plastic, and are designed to fit snugly around the endpin. By limiting the depth to which the endpin can be inserted, endpin stops help musicians maintain proper posture and prevent damage to the instrument or floor.