Lightweight and strength are two properties that can hardly coexist. For injection moulded applications using thermoplastic compounds, structural materials with specific weights below 1.4-1.6 g/cc are difficult to imagine. For most projects, densities of between 1 and 2 g/cc are not a problem, because they represent a considerable step forward compared to metals. However, a weight reduction of even a few grams can provide enormous benefits to all those applications in which the inertia of the moving parts, also linked to the weight of the part, is the problem to be overcome to obtain, for example, shorter actuation times and lower energy consumption. The conventional solution using blowing agents is not always easy to manage, and the results may not be up to the project requirements. The Latimass 67-04 D009 compound by Lati is an effective tool for obtaining a remarkable lightening of structural polyamide-based thermoplastics. Strengths of this Lati’s grade are both the matrix and the hollow glass spheres, a filler with very low apparent density behaving just like a blowing agent, but without the annoying limitations of systems based on the formation of gas cells in the polymer melt. In fact, the hollow spheres have a defined geometry that is not altered during the moulding process; once well dispersed in the compound, they are able to reduce the density of the resulting material by almost 20 per cent, but in a homogeneous and uniform way. The matrix of Latimass 67, instead, maintains the mechanical performance, so much so that the use of this compound as a master does not imply, in fact, tangible reductions in mechanical strength or embrittlement.