2N4443Thyristor by Motorola. Package: Early Motorola 90-04 , TO-127 (not later TO-225AA) (*) Spec: on state: 8 Amp RMS , blocking Voltage (DC or peak) = 400 V Download later Motorola 2N4443 datasheet: Status: NOS (New Old Stock) individually tested components : YES RoHS compliant: no **Note : £18 - £20 each on UK auction sites for untested generics . .. ours are GENUINE and tested ** ***Note, these will not be detected by a PEAK atlas DCA75 pro, but will always be detected by the PEAK atlas SCR100 testers ** (*) some with gold plated pins,others plain.