Spare bulbs:
The small bulb is the standard replacement for the Micro Meter, 1-10, 1-10-100 and 1-10-500 ml Bubble-O-Meters.
The large bulb is the standard replacement for the 10-100-1000 ml Bubble-O-Meter and QUAD 100, QUAD 500, QUAD 1000, QUAD 2000 and the QUAD 4,000 ml Bubble-O-Meter.
Spare bulbs:
The small bulb is the standard replacement for the Micro Meter, 1-10, 1-10-100 and 1-10-500 ml Bubble-O-Meters.
The large bulb is the standard replacement for the 10-100-1000 ml Bubble-O-Meter and QUAD 100, QUAD 500, QUAD 1000, QUAD 2000 and the QUAD 4,000 ml Bubble-O-Meter.