The TS-PB1 iButton Probe is a panel-mount iButton holder with integral red LED. The flying lead has 4 conductors, 2 each for the LED and the iButton connections (note that the panel-mount metalwork also forms the ground contact for the iButton - you may need to mount the holder using non-conductive panel material to avoid ground loops).

Suits panels of up to 3mm thickness
LED operation: 20mA DC at 2. 7V typical
Solid 303 stainless steel with blue nylon insulation