Background Trimming (Oval) Description
A red oval-shaped embroidered device edged with a 1/8 inch (.32 cm) red border bearing three 1/8 inch (.32 cm) yellow bars. The overall dimensions are 1 3/8 inches (3.49 cm) in height by 2 1/4 inches (5.72 cm) in width overall. 

History
The background trimmings for the 1st, 2d and 3d Battalions were approved 17 June 1986.

Source: The US Army Institute of Heraldry