10pcs Replacement 3 Way Connector Corners fits for grow tents that use 16mm(5/8") diameter tent poles. These corners are made of syndiotactic polystyrene (SPS), a new, highly-functional material well-suited for a wide range of applications. Compare to PPS, PC corners, our corners are more resistance to hydrolysis, chemical resistance, light weight, dimensional stability and heat resistance with a long-term heat resistance of 130°C.