Dynamo lights often use spade connectors, and spade connectors are crimped on using a crimp tool. This provides the exact right amount of pressure to effect a secure gas-tight joint between the stripped wire end and the connector, and without using a soldering iron. Note that the colour of the insulator matches the colour of the dot on the tool. Crimp tools used to be expensive, but these days Maplin sell them at a far more reasonable price.
