Pro-design makes the best if you have to have one. It is built into the reed spacers so no worries about leaks. Does a boost bottle work? Not for anything other than a crossover tube I would assume. The point is to maintain the momentum of the air traveling into one intake, then the intake suction stops reeds close and the momentum is transfered across the tube to the other side instead of a dead stop. I see no benefit of having a bottle for this. In reality it's probably more like a disadvantage as the bottle acts like a pressure buffer which would decrease the amount of transfer to the other side.