Wow... so boys skate, surf, drive off-road, ride motorbikes, create art and generally do cool stuff. Whilst girls wear bikinis, ride bikes (also in bikinis), shower (also in bikinis). I'm not normally one to vocalise my views on gender representation in a public forum, but you're right... a little embarrassing!!!
Anyway, rant out of the way, I couldn't hold back on that one, sorry!
If the brief is to explain and promote your idea, I thought it was interesting that you showed more than one concept sketch on the original poster, but think that you've nicely captured the lifestyle feel of the product, and clearly explained what it is with just a quick glance. The second poster doesn't feel as strong to me, it took me a little while to realise that the image of the product on the board on the right was actually on a board, it feels a little close to give it context. The controller feels a bit old-school, could you just interact with the device directly? Or is there another way of doing this that feels less clunky?
Looking closer at the illustration of the Burton Channel Mount, do you need to remove the binding to slide the unit in to the groove? What stops it sliding between the binding and the edge of the channel when it's inserted? Does it require tightening the screw to stop any wobble or scratching of the board? The fact that you've called it out and illustrated it brings up a few questions for me.