Millenium PD-669 Stage Double Bass Pedal

I'll just start by saying I'm a beginner.
This is a really good pedal, the feel is excellent for it's price. The pedal(s) are really heavy and sturdy. They sit nicely on the floor even with aggressive drumming.
It has a lot of areas that can be adjusted - a manual would come very handy.

The only downside to this pedal is that after a few rounds of kicking, the main beater became wobbly. It appears that the the mini screw that connects the beater body to the main rod of the pedal - this is quite hidden and you need to take the main beater aside to have access to it - was unscrewed.
Unfortunately the hex key (allen key) provided was just a bit smaller than the screw head so I could not screw it completely without damaging the screw head a bit (this I realised only when it was too late). So I used another allen key that fit well and managed to screw it all the way.