Note to Macbeth, Act 4, Scene 1, line 121:

"two-fold balls and treble scepters"

Act 4, Scene 1, line 121.
A "ball" is an orb, which is—according to Wikipedia—"a hollow golden sphere set with numerous precious and semi-precious stones. The Orb is surmounted by a cross, representing the rule of Jesus over the world." A scepter is a ceremonial staff carried by a monarch.

The passage is a tribute King James, a descendant of Banquo (see the Genealogy of King James VI of Scotland, I of England), and King of both England and Scotland when Macbeth was performed. The phrase "two-fold balls and "treble scepters" may be a reference to King James' two coronations. He was crowned in Scotland as King of Scotland and there received an orb and a scepter. He was crowned again in England, where he received an orb and two scepters. The two scepters probably represented the King's possession of the English throne and England's claim to the throne of France, though, as can be seen from the contemporary engraving below, the English monarch was also styled as "King of . . . Ireland."

James I of England, VI of Scotland,
with orb and scepter.

Image Source: Library of Virginia: James I