The Commission's report examines the proposed acquisition by Knauf Insulation Ltd of Superglass Insulation Ltd, both of which manufacture glass wool insulation products (also known as fibreglass or glass fibre) used mainly in loft and cavity wall insulation. The report considers the effects of the proposed merger on market definition in terms of demand-side and supply-side substitution; impact on competition in the relevant markets in relation to demand, capacity, imports and exports, market entry and pricing; and remedy options. The Commission concludes that the merger would be likely to result in a number of substantial lessenings in competition in the markets for glass wool loft insulation rolls, and glass and stone blowing wool for cavity insulation in Britain; and therefore recommends the prohibition of the merger as the only effective remedy.