The Tesi Switch NELLI V2 is the same size and feel as the EVH Wolfgang switch.  The switches feature an internal resistor so that it can be connected to any 9V battery without fear of instantly burning out the bulb.  Please note, the BLACK switch does not have an internal LED.

Specs:

Type: Momentary Push Button Switch

Operation Type: Normally Open (yes, this is correct for instrument kill switch operation. Included instructions show you how to wire it properly!) Can be wired as Normally Closed upon request.
Housing Material: Plastic
Mounting hole Size: 16mm
Mounting Panel Thickness: 1mm-6mm
Operation Pressure: about 5n
Operation Stroke: about 3mm
LED Rated Voltage:  12V 
LED Life: About 40,000 hours
LED Power Draw: 15mA
Contact Resistance: <50 mOhm
Mechanical Life: 1,000,000 cycles
Switch Rating: 3A/36VDC

What does all this mean?  You're getting a tough switch that will last a long time in your instrument and look good doing it!  

The switch is easy to install. If you have the slightest bit of skill with a soldering iron you can do it yourself. If you do not have that skill, you should have a guitar repair person do it.  

This package comes with everything:
(1) Tesi NELLI 16mm Momentary Guitar Kill Switch - This is the size used on the EVH Wolfgang and 5150 Guitars.
(1) Tesi Quick-Connect wiring Bundle that includes:
     (1) Black ground wire
     (1) White hot wire
     (1) 9V Battery Harness 
     (1) On/Off Rocker Switch
(1) Set of easy-to-follow wiring instructions

When used with active pickups and/or a stereo output jack (not included) the Tesi NELLI does not require the included on/off rocker switch.

Each Tesi Guitar Kill Switch is guaranteed against defect for one year from the date of sale.  Contact us for more details.

The Tesi Switch Difference:
We test every switch before packaging it.  As a result, the failure rate is less than 1%.  We package the 12MM and larger switches in a custom cut foam block and place in a small box for protection. The box also includes a couple of Tesi Switch guitar picks, as well as all the wiring necessary to install in an active or passive system, and we are always happy to help with installation questions.

If something does go wrong, our switches have a 1-Year Guarantee against defect or failure.