does anyone know anything about this trumpet? it is not on yamaha's site.

I googled it and found this on a musiciansfriend.com advertisement.

The Yamaha YTR-4335G Intermediate Trumpet in the key of Bb features .459" bore, 4-7/8" gold brass bell, Monel pistons, 1st valve slide thumb hook, main tuning slide brace, silver-plated finish. Includes case. All Yamaha wind instruments come with a limited 5-year warranty.

Yamaha YTR-4335G Intermediate Trumpet Features:

Key of Bb
.459" bore
4-7/8" gold brass bell
Monel pistons
1st valve slide thumb hook
Main tuning slide brace
Silver-plated finish

my ytr 1310 is Bb but it doesn't have a 1st valve thunb hook, or main tuning slide brace, it is silver plated though

Oops, I got the information on the wrong model. You might be able to find some information on this site though:

http://translate.google.com/translate?hl=en&sl=ja&u=http://www.geocities.co.jp/MusicHall/1497/YAMAHA/lineup/yamahalineup.html&sa=X&oi=translate&resnum=3&ct=result&prev=/search%3Fq%3DYTR%2B1310%26start%3D10%26hl%3Den%26lr%3D%26rls%3DHPIA,HPIA:2005-24,HPIA:en%26sa%3DN.

Or you might just ask the person who just posted what s/he knows if you have any specific questions in mind that you think s/he might be able to answer.