Product review (3 stars): The tube opening is not 27mm
Beware that these pole sockets are not quite as advertised. The description says they will fit tube size of 27mm. 1" = 25.4mm, so if these had a 27mm opening, they would easily work with 1" tube or even 3/4" IPS pipe or conduit (1.050 OD). My micrometer measures the inside diameter as exactly 1". It took a lot of force to insert my 1" tubing. The back side of these sockets say "25 CM", which is wrong since they are actually slightly over 25mm, or 2.5cm. Three stars because they will fit 1" tube, are metal, and seem fairly well made.