This through-hole speaker is great for projects where you need something that sounds better than a piezo buzzer but don't have room for a full-blown speaker. This 30mm diameter speaker is encased in plastic and will handle about 100mW of power.
This 200 pulse per rotation rotary encoder outputs gray code which you can interpret using a microcontroller and find out which direction the shaft is turning and by how much. This allows you to add feedback to motor control systems. Encoders of this kind are often used in balancing robots and dead reckoning navigation but it could also be used as a very precise input knob.
These are high quality Single Pole - Double Throw (SPDT) sealed relays. Use them to switch high voltage, and/or high current devices. This relay’s coil is rated up to 12V, with a minimum switching voltage of 5V. The contacts are rated up to 5A (@250VAC, 30VDC).
This is a white pair of micro metal gearmotor bracket extended, which enables convenient mounting of popular Sanyo-style miniature metal gearmotors.