Different guitar builders use different size truss rods and you need the specific type wrench and exact size for your guitar. Some truss rods are adjusted with a socket wrench while others use an allen wrench and others may use different type wrenches.
Under no circumstances should you ever attempt to use the wrong size truss rod wrench or you could strip the nut or socket and then you will never be able to adjust the truss rod again.
To find out what type and size wrench you need for your guitar, call Walden Guitars.
Walden Guitar USA information line (9am-5pm EST): 1-888-925-3369.
Then go to your local hardware store and purchase the specified wrench.
Also -unless your particular model Walden Guitar has an adjustable saddle, you will have probably have to sand the existing saddle down to lower the height should you choose to do so in an attempt to further lower your action.
Before attempting to file down your saddle by using fine grit sandpaper on a hard flat surface, obtain a spare saddle that is an exact match of your current saddle. If Walden won't sell you the part, try AllParts.com Guitar saddles on-line.
By having a spare, you can start over if you end up sanding it down too much. You can put a shim under it to raise it back, but it's better not to have a shim if you can avoid it.