You are buying 5 x He-Bands for Masters of the Universe vintage action figures. 
These are replacement leg connectors that are the same as the originals, made in Argentina by Lea Toys. They are made from injection moulded rubber the same way the original vintage ones were.
There are many videos on youtube showing how to replace your vintage action figure leg bands so please have a look at the process before you try it yourself for the first time, its fairly simple.
If you have any questions at all please let me know.
You will receive 5 leg bands, enough to repair 5 figures.