The manufacturers have fixed the lose switch thing frostypaw said can happen.
They are made from a very tough plastic. You can unscrew them to replace the batteries.
Unfortunately quicklinks are too big to fit the hole.
I get sent samples of just about everylight stick in creation. Most break far too quickly and/or are way over priced.
I smashed the crap out of these and were impressed by how durable they are and the price.
The are pretty light to swing with, however with time you can get use to the weight or tape them to some beamers
I am looking into a clip so they can be attached via quicklinks to chains etc. Otherwise you can just make a loop of string and then loop the string in the quicklink.