Power Transistor Cover TO-3

thingiverse

Many old power supplies designed for ham radio applications (Pyramid, Delta, etc.) feature exposed heat sinks on their rear sections, with bare transistor cases that remain ungrounded. It's relatively simple to short those transistors, thereby causing damage to the power supply. This protective cover fits snugly over the round lid of the transistor package, effectively insulating it from dropped large items such as coax connectors and cables.