From Halopedia, the Halo wiki
The gravity wrench is designed to be carried under-arm in a manner akin to the Type-25 Brute Shot. It consists of two large prongs which extent outward as they generate a compressed gravitic field via the use of either scaled down or archaic torsion drivers.
The origins of the gravity wrench remain obscure, as it bears little resemblance to the sleeker constructs encountered by the United Nations Space Command in the 26th century. Some theories presented by UNSC researchers suggest it may be a much older tool of Miner origin, and/or employed in an era predating even the Kradal conflicts. The method of operation used by the wrench has drawn some comparison to the gravitic generators grafted onto the Fist of Rukt - though the gravity hammers of the Jiralhanae have a much more military intended use than the gravity wrench.
The gravity wrench is one of many weapons designed for, and cut, during the production of Halo: Combat Evolved. It was one of several pieces of cut content recovered and restored via the Digsite project, and was later canonised in a Canon Fodder article. Due to the weapon's model being created in 1999, it is considerably lower in polygon detail than the weapons in release Halo: Combat Evolved. This is partially due to limitations of the era, and also due to the weapon's intent to be used in a third-person shooter; because of this the weapon was never intended to be particularly close to the camera on screen, and thus did not to be too detailed.
For Digsite, the weapon was subject to some small efforts at remastering by project contributor Ludus, who did some adjustments to the base model to add more geometry detail, bringing the weapon's triangle count up tenfold from the original 252 to 2,532 - as to ensure it doesn't look out of place among the other high-detail weapons in Combat Evolved. The changes made primarily affect the rounded edges, which have been given more definition to help them from appearing too low-resolution. A few details present on the original texture have now been given geometry detail for shadowing purposes - though the changes have only added in features already present in the original texture as to not detract from the original design. The original Macworld third-person model will be retained in the Digsite release as the third-person viewmodel, while the updated model will be used for first-person views.
Original 1999 model
Updated 2022 model