I sent a pair in a few weeks ago
Not sure what model you have ?
I have the Nikon Monarch binochs .
They come with a 25 year warranty .
I sent them in because they would fog up , had fine scratches on the lences and also a cracked eye cup extention .
I sent a copy of the original reciept , warranty card with serial number , a breif desription of the problem and the binoculars .
They came back with new eye cup extentions but were never cleaned or buffed .
I called Nikon , they sent me a call tag for shipping , so I sent them back with another letter of the issues .
Abought a week later I recieved a brand new pair .
Mine have the 25 year NO Fault warranty and were just 3 years old .
I have no complaints ...