I starting looking for a new duplexer for my 440 repeater and, of course, starting looking on eBay.
There were lots of choices that almost all looked the same so I starting digging.
I could see there were two major manufacturers of the offerings on eBay, and that the sellers shipped out of Asia.
Below is the manufacturer information:

One is made in China:
GCI Science & Technology Co.,Ltd
No.381, Xingangzhong Road
Guangzhou,P.O.Box 1003
Guangzhou 510310, P.R. China


While the other is made in Mexico: (and shipped from Asia)
Sistemas y Servicios de Comunicación, S.A. de C.V.
Laboratorio de Soporte.
Ave. 20 de Noviembre número 805
Colonia centro C.P.31000
Chihuahua, Chih., México.


Click on a picture below to go to the manufacturers website......
 

JIESAI (GCI Science) SGQ-150, SGQ-230, SGQ-350, SGQ-350D, SGQ-450, SGQ-450D

Click here for larger picture

SYSCOM 6366A33, 6366A23, 6366A13, 6336A9, 6336A2, SYS15333, SYS15332, SYS15331, SYS45334P, SYS45333P, SYS45332P, SYS45331P

Click here for a slightly larger picture

Click here for a slightly larger picture