They are only suitable for thin-walled pipes. and didn't fit. I had to trim them to make them slip. I was hoping they would be a bit more flexible but I was able to get them to work
Pros
SBD (pack of 8) 1-1/2 in OD Round (14-20 Ga for 1.34 to 1.43 in ID) Plastic Pipe Plug (1.5 in OD) End Cap - Furniture Tubing made of steel - chair leg - table slide insert | End caps for fitness equipment