5 barrel hinges:

Here includes: 5 barrel of hidden hinges and 5 barrel universal hinges. 5 barrel of hidden hinges are suitable for plastic,nylon or acetate glasses, and 5 barrel uniseral hinges are suitable for any material of glasses.

Material: all of them are made of high nickel, with nickel color coating.

 Here are even 7 barrel hinges as well.

such as TH-37,TH-38,TH-70,TH-24 etc. They are considered more durable than 5 barrel hinges.