AC188K Germanium PNP transistor by RS Components. Package: Package: TO-1 (in a NS257 aluminium or steel "brick") * Download shortform AC188K .pdf datasheet: for unmounted version see standard AC188 in related products tab above. Status: NOS (New Old Stock) Individually Tested components: YES RoHS compliant: no * block (7 x 7 x 15mm) which can be bolted down using an M2.5 bolt. (see photo)