Clip on rigid protective cover included. 3-year guarantee included. Other models to consider: The Casio fx85GT CW offers the same features and functions as the fx83GT CW, but with the added feature of being solar powered with battery backup. The Casio fx991 CW is Casio's most advanced scientific calculator, offering over 540 functions and connt to Key Stages 3, 4 and 5, to include A/AS level. Recommended and approved for use in Key Stages 3 and 4, to include GCSE, National and above, junior and parting. Permitted in all UK examinations where a calculator may be used. Recommended and approved for use in Key Stages 3 and 4 (to include GCSE, National and Higher, Junior and Leaving). The large natural textbook display shows mathematical expressions such as roots and fractions as they appear in your textbooks, increasing understanding as results are easier to understand.