Sandridge, Centerflag Products, and Racegun are currently the electro Cocker makers out there. I would suggest the latter two as they are simpler, cheaper, more reliable, use less gas, and can be taken off and have the Cocker returned to normal non-electro use if you decide you want to. Between the Race and the Centerflag Uprising frame it's a matter of personal preference. I believe that the CF is a little quicker to install, though, and is totally self contained within the frame which I think is a big plus. However, Raceguns have trigger bounce, which I adore.