Armour is ARM Friendly in other words offering arm protection by creating a more comfortable feel that no other string can offer. Of a circular shape, it is a co-polyester string which contains 20% of Soft Polyester and High Density Polyester, it is treated with alpha-olefin through a special production process which makes it solid but not hard on impact. The hold of tension is ensured by the multiple thermal treatments it has undergone during production that exalt its performance through time.