Amplifying Mechanic's Stethoscope With Probe Extension To Locate Tricky Engine Noises T1A-A1011 Comfortable, Spring-Return Ear Pieces Stay in Place While Working in Any Position Aluminum and Flexible Vinyl Tubing Construction & Unique Sound Amplification Chamber to Aid in Diagnosing Internal Motor Problems 4-Inch Steel Probe with 8-Inch Extension to Identify and Isolate Exaclty Where the Problem Is. Locate Trouble Spots within Engine Block With Ease and Speed Highest quality professional grade materials and built to last time after time.