The present invention encompasses compounds of general formula whereinR1 to R3 are defined as in claim 1, which are suitable for the treatment of diseases characterized by excessive or abnormal cell proliferation, and the use thereof for preparing a medicament having the above-mentioned properties. Associated methods are also described. The handle is snap fit or pressure fit to the lower rack. An additional embodiment utilizes outwardly-biased flexible fins that lock together in a closed position, with corrugated features in the fin inner surface that contact the trocar shaft such that, upon insertion of the trocar, the fins unlock and splay outward.