Box Construction is used in selected Klättermusen down products to help maintain an even distribution of down. The construction uses internal baffles instead of through seams, supporting consistent insulation across the garment.

In contrast to sewn-through constructions, this method reduces direct stitching between outer and inner fabrics, which can help limit the impact of air movement through the garment.

Box Construction is designed to support insulation by allowing the down to loft more evenly across the panels, contributing to thermal performance. When combined with high fill power down, it enables lightweight insulation while maintaining warmth during use.