The PICAXE is a great chip, but the programming interface is a bit bizarre, using a 1/8" stereo jack. Last time we looked, breadboards didn't have stereo jacks... Good thing these adapters are available!
The surface mount version of our smallest, but prominent, PICAXE microcontroller. Very popular in education due to its low cost and small size, but also popular in a wide range of hobbyist projects. Small but perfectly formed!