This Mangrove Jack's Gluten Free American Pale Ale kit allows you to make 23 litres of "real" GF beer at home. It contains de-glutenised malted barley rather than Sorghum (the commonest "alternative" to barley used in most GF beers), so it tastes like Real beer but without the consequences for gluten intolerant drinkers. According to the packaging, the Gluten content is <20ppm.
The kit contains 2.5kg of Malt Extract, a sachet of Mangrove Jack's M44 West Coast American Ale yeast and a pack of 50g of mixed Columbus and Cluster hop pellets. You will need to add 600g of dextrose to make it up to 4.6% ABV at 40 pints.