Luxilon LXN Smart 16 (1.30) 660' Reel The new Luxilon LXN Smart 16 (1.30) 660' Reel of tennis string is the first to adapt to a tennis players shots. The string actually firms up on higher impact shots and softens during touch shots. This string is a great, on-the-fly secret weapon. Recommended tension is between 40 to 48lbs. Features high control, power, and durability.