The Monoprice Lineman's Test Set is a professional piece of equipment designed for telephone installers, repair technicians, and phone system maintenance personnel. This durable, line-powered device is full of features for testing existing and newly installed communications systems for proper functionality.The bright red handset is both impact and water resistant. The rubber-covered keypad and large slide switches are designed for use with gloves, making this a convenient tool for line workers. The large, heavy-duty alligator clips support five different types of wire connections, including a bed-of-nails and an insulation piercing spike. A heavy-duty, spring-loaded belt clip allows the handset to be conveniently hung from a maintenance belt.The tester has a three-position volume switch, which can provide up to 12 dB of volume gain. The ring mode can be set to send either DTMF tones or rotary dial pulses. A three-position mode switch allows the tester to be set to Monitor, Ring, or Talk modes.The handset includes an automatic last-number redial function, which is capable of repeating up to 31 digits. It also features a number memory storage capability, allowing the technician to store up to 10 different numbers of up to 15 digits each, including the insertion of 3-second pauses for use with trunk lines. A pre-installed CR2032 lithium battery maintains the stored number memory and can be easily replaced by removing two screws and opening the handset.To assist in line testing, the kit includes a 5-inch, 4-wire RJ11 test lead with spade lugs on the ends of each wire. Additionally, a 2.5mm headphone jack allows the technician to utilize a microphone/headset unit instead of the handset speaker and mic. When not in use, the headphone jack is protected from moisture with a rubber cover.*** 30-day easy returns. No restocking fee. Free lifetime technical support. 1 year warranty. ***