The usefulness of manipulatives in the primary maths classroom has been frequently asserted. The purpose of this study was to compare the effectiveness of two different types of manipulatives, bendable and rigid, as aids for the conceptualisation of 3D solids from 2D nets (fold-outs of solid geometrical shapes) within the NSW Stage 2 Mathematics Curriculum. Contrary to initial expectations, the bendable nets, although more attractive to pupils, did not prove superior to the rigid variety. In fact, the most noticeable advances in conceptualisation followed teaching experiences using the rigid nets. Although this was a preliminary study and the sample sizes were too small to support solid conclusions, it is suggested that the data were sufficiently robust to warrant further investigation. We suggest that the lower than expected results for the bendable nets may be explained, partially, by the reduced conceptual demands made by these more ‘obvious’ shapes. Correspondingly, the greater mental visualisation required when working with the rigid nets may have produced heightened student conceptualisation.