Featuring the Desert Snow logo, this Stethoscope is perfect for conducting the "echo test" which was developed by Joe David, the founder of the Desert Snow Training Program. This test has been adopted by numerous federal, state, and local agencies all throughout the United States. The test can be used to check for contraband concealed within both passenger and commercial tires. It can also be used to check for concealed contraband in commercial fuel tanks.
1. Passenger car tires must have a minimum of 20 psi and commercial tires must have a minimum of 50 psi for the echo test to be effective. If a tire does not have enough psi, you will hear a thud when conducting your test.
2. Using the Clock System, place the head of the stethoscope on the tread of the tire in the 10 O’clock position.
3. Tap the tread at the 2 o’clock position with a solid blunt object such as the hardened steel pry bar or hammer which is located in the Desert Snow Tool Kit. Tap as hard as you can without hurting your ears, and only tap one time. You may repeat this process as many times as necessary for clarification.
4. If you hear a continuous echo sound (piiiiinnnnnggggg), this would indicate that nothing is blocking the tapping sound from reaching the rim and bouncing off, indicating that the tire contains nothing but air.
5. If you hear a dull sound or thump when you tap the tire followed by no echo sound, this would indicate that something is blocking the tapping sound from reaching the rim and therefore no echo sound can be heard. This would indicate that something besides air is inside.
Of course... this tool is also inclued within the Desert Snow Vehicle Search Tool Kit.