Rhythm Band C Major Pentatonic Boomwhackers Set

I cannot find an explanation of what these are and how to use them. (I know nothing about music.) They were recommended for my special needs daughter.

We would like to buy these for our families annual News Years Day gathering. Which sets or sets would you recommend for a group of 15 kids and adults?

How easily do these break? Will they withstand being struck on something with an edge?

Can I use them outside? Thinking of attaching them to a fence.