The Mighty Strap of Leather is an upper-body slot armour, which consists of the player being half naked with only a leather belt being coiled around various places, and excludes any undergarments or armour from being worn on top of it. The armour has decent defensive strength and also grants the player a great strength bonus.
While mapping the 2nd Floor's Labyrinth, Kirito found the armour in one of the treasure chests that he came across. He was planning to equip it at the nearest safe zone due to the armour having decent stats. However, after Asuna encountered a Lesser Taurus Striker, which had a similar armour equipped, and called such apparel as sexual harassment, Kirito decided not to equip the armour. Though, since he did not want a rare item go to waste, he decided to give the item to Asuna. But after mentioning that he had found a strap-type armour and seeing the glow in Asuna's eyes turning three times colder, he suggested giving the armour to Agil and Asuna told Kirito to give the item to him during the raid of the next Floor Boss.