It's a tube, there are many different brands out there and we have tried them all, these ones are the best.
Shraeder (Car type) Valve unless specified.
22" TUBES ARE S&M TUBES, THATS ALL WE COULD GET IN 22'' AND HENCE THE PRICE DIFFERENCE.
PV stands for Presta valve.
Normal 20 x 2.4" bmx tubes available here.