Quick question about hooking up a 110v Solenoid Valve?

This might be a dumb question but I don't want to mess anything up. I just started looking over everything and I noticed that the lead wires on my valves are the same color? Does it make a difference which way they get hooked up? If I hook it up backwards will it stay energized?

I have these valves - http://www.electricsolenoidvalves.com/1-2-110v-ac-electric-brass-solenoid-valve/

Most of the solenoid valves have a steel core and a coil around it. It doesn't matter what + or - is.

The information for your valve is confusing. The title says "110V AC" and the text on that page says "110V DC Coil". Since 110V is mains voltage, I assume it is ment for an AC voltage of 110V.

Do you want to control them with an Arduino ? How ? They have the same valve with a 12V DC coil for the same price. That would go well with the Arduino, using a logic level mosfet and a flyback diode.

AC voltage changes 'polarity' 60 (or 50) times a second so devices that are powered by AC voltage are not polarity sensitive and you can wire either way.