Choosing the Right Ultrasonic Bubble SensorBubble Sensors

There are many factors that go into choosing the correct ultrasonic bubble sensor for a given application. The primary differentiator between our off-the-shelf bubble detectors is the size of the tubing that can be used with them. We carry standard sensors that will work with almost any plastic or rubber tube between 1/16” outside diameter and 1/2” outside diameter. 

Beyond that, you will need to choose from our two bubble sensor product lines:

  • Our first product line, the “AX3X” product family (e.g. A230, A330, A430, etc.), was designed to offer the most options possible. Each model is fully configurable and allows you to select between Metric or Imperial threaded inserts for mounting, whether you need a red/green LED output indicator, a TTL vs. PNP output, and whether the test feature is enabled or disabled. 
  • Our newest ultrasonic bubble detector product line, the “AX1X” product family (e.g. A210, A215, A310, etc.) was designed from the ground up with our medical device OEM customers in mind. Everything about the design was streamlined to offer the most requested features including a test feature that is enabled by default, an input voltage down to 3.3VDC, a connector on the back to allow us to easily offer any cable length without changing the base design, and a mounting configuration that offers superior levels of ingress protection. We have streamlined our production and calibration processes to offer the lowest prices possible. 

Use the table below to compare features between our newer AX1X product family and the classic AX3X bubble sensors. 


AX3X Series (A230, A330, A430, etc.)

AX1X Series (A210, A310, A410 etc.)

Tube OD






(A230, A240)



















Tube Material

Soft Plastic

Rigid Plastic


Glass, Ceramic

Custom solutions required

Custom solutions required


Custom solutions required

Custom solutions required

LED Indicator Available


Test Function


Input Voltage

5-15V or 5-24V 

3.3-5 VDC


TTL 3mA Max, or 

PNP 300mA Max

TTL, 3mA Max

Mounting Options

Threaded Insert (M2.5 or #4-40)

Through Hole, Optional Gasket for Ingress Protection†


12” cable with flying leads

No cable, Molex connector on back

Standard Response Time‡

50 microseconds

100 microseconds





Bubble Sensor Application Solutions


See our Bubble Flow Rate Calculator for more information about response time.


Other Resources:

Bubble Sensor – Tubing Selection

Custom Tubing for Standard Bubble Sensors

Bubble Size Calibration

Bubble Sensors – Test Pin

Bubble Sensors Technology Overview


†Contact us for a CAD model of recommended through-hole mounting configuration or if you would like more information about our bubble sensors.