(click on pictures to enlarge)
The Eggens-Hambler Co. was a partnership formed in the early 1920s by John Eggens and William Hambler, both of whom were Waterman employees.
Eggens-Hambler products were marked with the initials "EHCO" in an oval.
Although the company's products are usually described as just above average, the larger piece at bottom is simply outstanding in every way. Compare this pencil with the left most example on my Chilton page.