2 brake part questions

[irondiezl3]

first one is the red disc brake quite tube you use to put on the back of pads to help with noise can i put it on now even though im not changing my brakes for a couple days or do you have to put this stuff on and immediately install to calipers? second look at this page im so confused these are the same exact rotors yet once twice the price with no explination wtf!!


https://www.napaonline.com/Search/Compare.aspx?R=UBP86913_0186328945+UBP880130_01863 28963+

[AXLE]

You put the disc brake quiet on the pads as you install them. No need to wait for it to "dry", it really doesn't cure, and it stays gummy to dampen the pad vibrations that cause the squealing noise.