I have several, some are curved, some straight. Some really thin, some not so.

I buy them at drug stores, walmart etc.

They can be cheap, or not so cheap.

Having several lets you try out different ones to see what you like, or use different ones for different etch types.

They are really good at getting close and in tight spots. You can also get a good clean cut, as opposed to xuron or other angle cutters that sometimes don't go all the way through thin brass or can't get close enough.

That's not to say they are perfect, if you aren't careful, the brass can tilt and go between the blades.

Just be careful.