The castelli mortirolo 4 jacket the mortirolo 4 jacket is a favourite among cyclists because itrsquos exceptionally good in a wide variety of conditions this jacket keeps you warm but also vents a lot of moisture out the back thanks to a thermal warmer fabric for added ventilation there are zipped front vents castelli mortirolo 4 jacket features gorereg windstopperreg x fast fabric on front is windproof and water resistant back in warmer to prevent overheating front zippe