Simms Slack Tide LS Shirt, An articulated, UPF-50 fishing shirt with vents to dump heat and keep you cool under a hot sun.Every day on the water offers fresh experiences. Our ventilated, UPF-50-rated Slack Tide Shirt brings angler-driven versatility to the ever-changing adventure. This men's long-sleeve fishing shirt wicks moisture to keep you cool and features articulated arms and four-way stretch panels for natural, unrestricted casting.