Reliable Egg Scale - 1st generation  Wooden base

With its wooden base, this is the first generation of egg scales by Reliable Manufacturing Co. of Los Angeles, California. They made three generations of horizontal rocker scales on metal or wooden bases. The beams were metal or pot metal.

The scale could grade a variety of sizes through a combination of a flip weight on the beam and loose weights that hung on a notch in the beam or sat on the egg holder. The example shown in the photo was to grade chicken eggs, ranging 16–27 ounces per dozen. Most varieties were also made in a version to weigh turkey eggs and had a range of 30–44 ounces.

This model was followed by a metal-base model about 1943. Both wooden and metal bases had a lip to allow the scale to sit securely on a standard egg crate for easy packing. 

The manufacturer's information was stamped on the base in ink (no longer visible on this example). Circa 1930 advertising said it was manufactured by Poltriquip Manufacturing Co., Ltd., of Los Angeles, but it was still called the Reliable Egg Scale from the Reliable Manufacturing Co. It sold for $2.90.

Directions for use were usually included.

References:
See Exhibits > What Is an Egg Scale?
For more information about company history, go to Maker Histories > Reliable Mfg.
Charley Amsbaugh, North American Egg Scales from ABC to Zenith, ECKO House Publishing, 2011, scales 60–62.