Castelli's Goccia jacket is a minimalist waterproof and windproof jacket for packable protection from the elements. The Tempesta Stretch fabric is fully waterproof with a 10,000mm hydrostatic head and taped seams. It also breathes exceptionally well with a moisture vapour transfer rate of 20,600g/m2/24h to minimise sweat build-up on the inside. The mechanical stretch in the fabric means it hugs the body closely to eliminate wind flap and moves with you for excellent freedom of movement. All the little details are taken care of too with a vent in the back for enhanced breathability and an extra long tail to fend off rear wheel spray. There are reflective details at the hem for nighttime visibility and the front zip has a storm flap to keep the wind out. The best bit is that you get all this in a 204g package that fits in your jersey pocket!