Tannus Armour Tubeless Gravel Tire Insert – 700 x 33-47mm Single. Tannus Armour Tubeless inserts are the result of years of top level multi-cell foam manufacturing mixed with extensive professional riding experience. At the heart of Tannus is the patented Aither Technology; a multi-cell foam compound that forms the structure of the Armour. The inserts are designed to displace small impacts while offering a spring-like rebound for a smooth yet playful ride.