Please note that there is no difference between ICD2051SC and ICD2051SC-1. They are the same and similar in form, fit and function. The ICD2051SC parts that do not have suffix "-1" are the same version as those with "-1". The "-1" indicates a Configuration/Option Number and it does not alter the physical or electrical properties. The non-inclusion of the "-1" is the result of the stamp marking size pattern and the positioning on the part being stamped.