Telecasters are normally supplied with two pickups as standard but originally available with just one (called the Esquire,) and also now with three. Also numerous variations with humbuckers may be ordered however, that distinctive sound belongs with the fat bridge pickup and some clever internal electronics.
A modification to the electronics of the Telecaster is to replace the volume and tone controls with two volumes. This arrangement allows the two pickups to be mixed for more variation in tones. Furthermore, if the neck pickup is rewired to be “Out of phase” with the bridge the range of mixed tones has to be heard to be believed. Remember that the original tones are still retained but a range from subtle jazz to piercing treble is now available. Also, no drilling or alteration to the look of the guitar is required and no batteries are needed.
If you don't own a Telecaster but like the sound the same electronics can be incorporated into any instrument to emulate that special guitar sound you want.