From their website;
"Brew Enhancer 2 (1kg) improves the flavour, body, mouthfeel and head retention of your favourite brew. Coopers Brew Enhancer 2 contains dextrose, maltodextrin and Light Dry Malt. The dextrose will ferment out completely with no residual cidery flavours whilst the maltodextrin does not ferment thus improving the body, mouthfeel and head retention. The Light Dry Malt, being 100% pale malt, will further add to the body and increase the malt character of your favourite brew. Great for use with any beer styles where a fuller, maltier flavour is preferred."
The whole package is added to your wort. I've used it in a couple of their ales and in my opinion it does improve the final product