The phrase "a double arrow" is correct and usable in written English.
It can be used in contexts where you are referring to a symbol or representation that indicates two-way direction or movement, often in diagrams or illustrations.
Example: "In the flowchart, a double arrow indicates that the process can move in both directions."
Alternatives: "two-way arrow" or "bi-directional arrow".
A single arrow between them denotes an irreversible reaction, a double arrow a reversible reaction.
The results of the calculation show that in the region where the front of the landslide has met the topographic obstacles along the path, indicated in Fig. 12 as a double arrow, the subaqueous velocity would have been lower than 20 m/s, much less than the velocities required to reach the top of the mound points A D.
His other facial tattoos include an old nickname ("Stardust," a reference to the drug dealing days of his teenage years) under his left eye, a double arrow tattooed below that, and praying hands with the words "It's all worth reaching for" going across the left side of his head a tattoo he and a group of friends got, memorializing a friend who passed with the same tattoo on his arm.
The region marked with a double arrow represents the part of the cell whose intensity is expected to be dominated by cytoplasmic For3p-3GFP.
Unbeknownst to the subjects, the subliminal stimulus was either an "X" sign or a double arrow pointing to the same or opposite direction as compared with the target stimulus.
They are indicated by a double arrow respectively.
This tunneling solution is depicted in Figure 10b, where the reliable transport layer connections are indicated by a double arrowed solid black line.
This setup is depicted in Figure 10a, where the reliable transport layer connections are indicated by a double arrowed solid black line.
The actual reliable transport layer connections are indicated by a double arrowed solid black line, while the perceived reliable (unreliable) transport layer connections are indicated in a solid (dashed) grey line.
A double-arrow-shaped clip design on the Three Bridge writing instruments referenced a distinctive feature of the watch while three windows in the pen's body show the ink level — again a nod to the power reserve indicators on the watch.
When I started to look at the scene more closely, I noticed that at the base of the rock was a graffitied double arrow, almost certainly a reference point for some refugee boat, which is one of the reasons why the place was so heavily patrolled by the army.
