Material: Made of plastic, the accessories can withstand impact and not easily broken. 5 types of connectors: There are 5 types of connectors to choose from, flat 3-way, flat 3-way right angle, 4-way flat, 4-way right-angle, 5-way, to meet your different greenhouse construction needs. Stable support: The connector can support your greenhouse from stably and will not be easily blown away in windy or rainy weather. Inner diameter: inner diameter is about 16mm, suitable for PVC pipe or metal pipe with outer diameter of 16mm . Wide range of applications: suitable for flower stands, greenhouse frames, etc. Ideal for supporting any structure, as well as creating frames; ideal for displaying items such as greenhouses, photo frames, furniture, shelves, pool products, etc.