Chronolometer

From Acquisitions Incorporated, page 220.

Description
Wondrous item, very rare (requires attunement).

While attuned to this device, you have a +1 bonus to Intelligence saving throws. The first time you attune to the Chronolometer, you choose one language you don't know. You subsequently know that language while attuned to the device.

Time Bandit. At the start of your turn, roll a d6 (no action required). On a 1-3, you slow down time, gaining an additional action on your turn and doubling your speed until the end of the turn. On a 4-6, you go forward in time to warn yourself of what is to come. The next time you fail a saving throw, attack roll, or ability check, you can reroll the check and take either result. Once you use this feature of the Chronolometer, it cannot be used again until the next dawn.

Fate Swap. As a reaction when a creature you can see within 30 feet of you takes damage, that creature gains an additional action if it is the creature's turn, or can take an action immediately even though it isn't the creature's turn. Once you use this feature of the Chronolometer, it cannot be used again until the next dawn.

Part of a Whole. While this component is not installed in the Orrery of the Wanderer, its magic might function sporadically or with unpredictable side effects, as determined by the DM.