Buy with Confidence: With Monoprice's Lifetime Warranty on all Cables, you can rest assured we stand behind our products and our customers. Earphone permits use in noisy environments LED light for use in dark environments The Tone Generator with Probe Kit specifications are: Tone Frequency: 1kHz Maximum Transmission Distance: Up to 2 kilometers Maximum Operating Current: Less than 10mA Tone Modes: 2 tones Compatible Connectors: RJ45, cable clip with RJ11 connector Maximum Signal Voltage: 8 Vp-p LED Displays: Wiremap, Tone, Tracing Voltage Protection: 60 VAC, 42 VDC.