Is boxing tennis hat useful?

[michi972]

Something like this.
http://mmashop.pl/pozostale/1329-fanga-focus-pileczka-sprawnosciowa.html
I'm considering buying it.Is it worth?

 

[AndyMaBobs]

Yes, it will be very useful, but only buy it if it's more expensive to make one. Otherwise get an actual tennis ball, some elastic string and a baseball cap and make it yourself.

 

[Sinister]

Yeah you can make them for less than 3 bucks.

 

[Hi-Tech]

It is the most useful

 

[Gandhi]

How the F do I not know about this - I am making / getting one