Concise Bible Dictionary:

Shackles – (from sometime before 1860)
Shackles – (from sometime before 1860)

“270. Prisoners Fettered” From Manners and Customs of the Bible:

2 Samuel 3:84. Thy hands were not bound, nor thy feet put into fetters.
Strigelius supposes that David meant, by using this language, to distinguish Abner from those criminals who are carried to execution with their hands tied behind them; and from soldiers who are taken captive in war, and have their feet fastened by fetters to prevent their running away. For a description of fetters see note on 2 Kings 25:77And they slew the sons of Zedekiah before his eyes, and put out the eyes of Zedekiah, and bound him with fetters of brass, and carried him to Babylon. (2 Kings 25:7) (#360).

“360. Prisoners Blinded Fetters” From Manners and Customs of the Bible:

1. Blinding has long been a common Oriental punishment. See Judges 16:2121But the Philistines took him, and put out his eyes, and brought him down to Gaza, and bound him with fetters of brass; and he did grind in the prison house. (Judges 16:21); 1 Samuel 11:22And Nahash the Ammonite answered them, On this condition will I make a covenant with you, that I may thrust out all your right eyes, and lay it for a reproach upon all Israel. (1 Samuel 11:2). In Persia, during the time of the younger Cyrus, men deprived of their sight for crimes were a common spectacle along the highway. This penalty is still inflicted by the Persians on princes who are declared to have forfeited their right to the throne. Chardin states that one mode of blinding was by passing a red-hot copper plate before the eyes. This did not always produce total blindness, and sometimes the point of a dagger or of a spear was thrust into the eye. The Babylonians and the Assyrians, as well as the Persians, made use of the same cruel punishment. Frequent representations of it are found on the ancient sculptures. The engraving represents part of a scene from a marble slab discovered at Khorsabad. The Assyrian king has several prisoners brought before him to be blinded. In his left hand he holds the cords at the end of which are hooks inserted in the prisoner’s lips. See note on Isaiah 37:2929Because thy rage against me, and thy tumult, is come up into mine ears, therefore will I put my hook in thy nose, and my bridle in thy lips, and I will turn thee back by the way by which thou camest. (Isaiah 37:29) (#572). In his right hand is a spear, which he thrusts into the eyes.
2. Fetters were of various shapes and materials. Those which were put on Zedekiah were made of brass or copper; so also were those with which Samson was fastened (Judg. 16:2121But the Philistines took him, and put out his eyes, and brought him down to Gaza, and bound him with fetters of brass; and he did grind in the prison house. (Judges 16:21)). There is in the British Museum a pair of bronze fetters, brought from Nineveh, which weigh eight pounds eleven ounces, and measure sixteen and a half inches in length. These probably resemble the fetters put on Zedekiah. “The rings which enclose the ankles are thinner than the other part, so that they could be hammered smaller after the feet had been passed through them. One of these rings has been broken, and when whole the fetters may have weighed about nine pounds” (Sharpe's Bible Texts Illustrated).