SK100 PNP General-Purpose Medium Power Transistor (TO-39)

Before plastic TO-92 packages became the overwhelming default, many general-purpose transistors shipped in metal TO-39 cans like the SK100, which offer somewhat better heat dissipation and a more rugged physical package at the cost of a larger footprint. It handles the same basic medium-power PNP switching and amplification roles as other parts in this current range, making it a practical substitute whenever an older schematic or classic audio circuit design specifically calls for a metal-can PNP transistor rather than today's more common plastic-packaged parts.