Macpac’s legendary medium-size alpine pack is ready to tackle mountains, summits & multi-day adventures. Macpac's Az Tec fabrics are designed to withstand tough terrain, wet weather & dense bushl&. Their unique blend of hard wearing, long staple cottons, & abrasion & rot resistant polyester fibres create superior weatherproof, hard-wearing fabrics. The strands are plied together & tightly woven into a durable cloth which is saturated in a blend of resins & waxes to provide weather-proofing. In wet conditions, the natural swelling of the cotton fibres fills the spaces between the fibres to enhance the fabric's weather-proofness even further.