You are buyding on a used in excellent condition Quantel compact touchscreen A-scan Biomter. The unit is clean, portable and very accurate. Can be used for both immersion and contact biometry. The unit works fine with no issues apart from the fact that the touchscreen sometimes stops responding to touch, but the unit continues to respond normally to the keyboard and its touchpad. It canbe upgraded to Pachymetry and B-scan if you buy these probes. These are available from Quantel. Comes with 90 days money back warranty for any other issues.