They are two different cases. Super Thin is our co-moulded case in Black, Navy and Dark Sand, with 1.3 mm sides and a soft touch finish. It carries our Limited Lifetime Warranty. 

Ultra-Thin Aramid is our thinnest case ever — 1.2 mm at the back and 0.6 mm at the sides — made from woven aramid fibre in black. It is designed for daily bumps and scratches rather than serious drop protection, and it carries a one year warranty. 

If protection matters most, we would point you to Limitless or Clarity.