The following instructions are taken from an instruction page faxed to be my Somborn LLC, and is reproduced here with permission

Aqua Magnetic Locator

LOCATES VALVE BOXES, SURVEYOR'S STAKES, MANHOLE COVERS AND OTHER CONCENTRATED FERROUS METAL OBJECTS.

The following is a series of steps in the use of the Aqua Magnetic Locator.  Please follow them carefully for 100% satisfaction:

1. Open flap in leather case. (Instrument need not be removed from case.) Turn AQUA on its side, bottom of case toward you, NW, N, NE dial level. In this position, your AQUA is a compass. Point dial portion north until red end  of needle points exactly at "N". You now have true north position.
2. Turn AQUA u[pright, point gold arrow on the leather case to "N", as was  indicated by instrument in step #1. (When leather case is very new, it is  helpful to fold the flap down firmly so that it will remain in position when in use, and not obscure the dial.) Using carrying strap, lower instrument to just a few inches above ground, holding instrument carrying strap over four fingers. Holding strap by four fingers minimizes chances of instrument twisting out of  position as you walk. Be sure that "N" is still pointing north.
3. Begin "walking" the instrument in parallel paths, about 12 to 15 inches  apart, until the red end of the needle dips and the black end of the needle appears. Find the point of maximum reading: that point at which black end comes nearest to "90" mark. At this point, walk at right angle to former path, still keeping instrument pointing toward north, until maximum reading is found on  right angle path. This is the location of missing valve box or stake.

When object to be located is very deep in the ground, or heavily covered, a  full deflection to "90" mark cannot be expected. In cases of this kind, "70"  or "75" may be the best reading obtainable.

In areas where there are high voltage overhead wires, there is usually electrical disturbance, which will cause the red end of the needle to show on  dial. This does not hamper location operations. When over the object, red end  will disappear and black end will appear on dial.

Where shrubbery or other obstructions prevent the strap method of holding  instrument, AQUA may be removed from its leather case and metal rim pulled up  and used as a handle. However, whenever possible, keep AQUA in leather case, as  a protection against possible damage from bumps and jolts.

Somborn, LLC DBA Aqua Locator
141 W. Xenia Avenue
PO Box 579
Cedarville, Ohio 45314-0579
Phone: (937) 766-2451