*reminiscent of affluent young Jewish women of the Upper East Side.

Ruth has a sleek purple design with beauty spot. She seems to be the "leader" of the two. She seems to be heavily attracted to Bender, giggling shyly at him and becoming saddened when Bender stops making out with her to make out with Esther, giving a disappointed grunt. The camera perspective changes to be from Ruth's point of view showing her looking sadly at Bender and Esther making out.

Esther is the more quiet of the two, and seems to be the more sensitive. She has metal plaiting in the shape of a 20s bob, light steel grey "skin" and wears either a peach colored bikini or a two piece peach colored dress with pink feather boa, along with a small choker set with a green stone. Esther has blue eyes and unlike most characters on the show, lacks the distinctive overbite of Matt Groening's characters, yet the "teeth" on her mouth give the impression of a bucktoothed young woman. Curiously Esther's mouth is constantly moving, a rarity among robot characters, with her "lips" able to smile or frown, making her the most expressive robot character on the show by facial expression. She's a waitress in a robot strip club.

They seem to be possibly modeled after Roxie Hart and Velma Kelly, the two anti-heroines of Chicago. They also share traits with Patty and Selma of The Simpsons. Esther is a blonde like Selma's natural hair color. They seem to enjoy blintzes as a snack, a popular Jewish pancake. Ruth went to Vasser.
Esther's neck can extend like a rock em sock em robot. Esther's hairstyle is very similar to Dot Matrix from the film Spaceballs. Ruth's thick Brooklyn accent and overall appearance and personality seem to be based on Marisa Tomei's portrayal of Lisa Vito, from the film My Cousin Vinny. Both take their names from books of the Old Testament: Ruth the great grandmother of King David, and Esther, the Jewish queen of Persia who saved her people from a bloody massacre, and instigated the festival of Purim. Notably The Book of Esther is one of only two books of the Old Testament that doesn't mention God. Fitting in with the science fiction theme of the show, Esther means "star". Esther is also shown against a backdrop of stars in her first canon appearance. While Ruth's mouth shape remains static, Esther's mouth changes shape to express her emotions, with her lips constantly moving. They will often giggle appreciatively or not seem to notice or care when referred to as sluts, skanks, floozies, and other derogatory or insulting terms, but will quickly become enraged if referred to as "trashy": notably when referred to as a "trashy robo slut" by Bev, Esther, despite being the quieter of the two, instantly responded by telling Bev "trashy? at least I don't put for quarters".
Curiously, despite being robots, both are very sensitive to heat and cold, notably Esther dislikes the cold while Ruth dislikes the heat. They both have degrees in political science.*