Here's one thing to keep in mind about ventilation--the knots are not permanently fixed in a specific direction. They can be if you use knot sealer. But in a normal unit the hair is ventilated in the direction that you specify. But the knots 'turn' after a few washings. So if you order a freestyle unit and you style it in a left break style than eventually the knots will turn in that direction as you comb the hair in that style.
Regards,
John
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