What are the springs in the back of a Stratocaster?
In the Stratocaster, the coil springs are located in the rear of the body, under the backplate, and it is essential that these springs don't touch any other parts, such as the woodwork or the backplate itself.
Do noiseless tremolo springs work?
The new polymer coated supposedly "noiseless" tremolo springs are worthless. If you use a med-high gain amp, you'll likely hear spring noise and these coated springs are supposed to reduce or eliminate it. They DO NOT.