These are connectors fitting 3/4" shelve poles, so its diameter slightly smaller than 3/4", so it can get into the pole, Compatible with H*PE* Toug* Brand from WAM*RT, not compatible with 1" poles, cause this pole connector is very small. OUR wire shelving pole connectors are constructed of heavy duty metal. They are double male threaded connectors which are used to connect two poles together to assemble the shelves. Simple to install and remove. Universal size/ fits most 3/4" threaded posts. Due to that there is post thickness difference on the market, like 1mm and 1.2mm for 3/4", there maybe situations that it won't thread based on the post thickness, under this situation, with a little extra tape on the top end would help get a tight seal. Package:8 pieces of 3/4" shelving connectors