The one in the picture is more like a Judo gi, exceptionally thick and strong, Brazilian Ju Jitsu is more of a sport (like Judo) than a self defence system.
We wear light or medium weight karate gi's, as in normal Ju Jitsu you don't use the gi to throw, except for a 'lapel and shoulder throw'.
Buy one of these: (U$S 2)
Dismantle It, and put it into the knife's handle....It uses only an "A" battery.
I use them for little electronic fences....
My dog learnt where NOT to pee, in almost 3 nasty shocks....