This item is quite the hype with PolarStar Fusion Engine users.  We were actually able to get a hold of a couple kits from PolarStar. This kit includes everything needed to convert your Fusion Engine into an ambidextrous BB slinging machine with the exception of the spring that goes beneath the selector switch ball bearing. This spring is meant to be provided by your existing selector switch. 

Complete kit includes:
1x Fusion Engine Ambidextrous Bar
1x VFC Left Selector
1x VFC Right Selector
2x Selector Screw
1x Selector Ball Bearing

We will try to get more made by PolarStar, but we can't promise anything short term, so get yours while you can!

Disclaimer: Some modification may be required to fit non-VFC lower receivers.