Like the 27th and 37th Engineer Battalion, the designs of the 30th Engineer Battalion organizational flash (“flash” for short) and background trimming (“oval”) is based upon those of the 20th Engineer Brigade, reflecting the fact that the Battalions were all components of the 20th Engineer Brigade when their flashes and ovals were approved. The only difference in the designs of the Battalion’s insignias is the number and placement of the white horizontal lines at the center, while the Brigade insignias have no horizontal white lines.
As the first of the Battalions to be assigned to the Brigade, the 27th Battalion has a single white line that reaches from the left and right borders until it reaches the white triangle; the next oldest, the 37th, has that line plus one above it that reaches roughly halfway to the triangle. As you can see here, the 30th has two additional white lines that reach roughly halfway to the white triangle.
With the inactivation of the 30th Engineer Battalion in 2015, both the organizational flash and the background trimming are no longer authorized for active-duty wear.