There are enough connectors to handle railing needs of any size, and you can have some to spare when you're done, or share with friends and family to help them complete their own stair or deck railing projects. Made of rugged black plastic with excellent impact, compression and deformation resistance, it stands the test of time. The circular section has an outer diameter of about 0.64 inches /16.2 mm and a height of about 0.685 inches /17.4 mm, which is perfect for rails with an outer diameter of about 3/4 inches, but also for other rails with an inner diameter of 0.68 inches. This precise dimensional fit ensures the stability and reliability of the connection, making your railings even stronger and more durable. The installation process is just as easy, these stair balustrade connectors are pre-drilled and can be easily secured using only a power drill and #8 deck screws (purchased on your own). Whether it is a DIY enthusiast or a professional architect, it is easy to get started and enjoy the fun of building quickly. What's more, these plastic rail connectors are not only practical, but also versatile. They are widely used in a variety of architectural scenarios, such as stair assembly and deck construction, to stimulate your creativity and bring your unique ideas to life.