Loon™ - Deep SoftLoon Deep Soft Loon Deep Soft is a non toxic tungsten putty designed to help anglers quickly and precisely adjust fly depth and presentation on the water. This reusable, biodegradable putty sinks fast and can be easily applied, removed, and reshaped to match changing fishing conditions. The charcoal colored tungsten formula offers an environmentally friendly alternative to traditional lead split shot while providing the dense weight needed to get