Like all mirrors, the Hand Mirror has the ability of reflecting light due to its smooth surface, allowing the user to inspect their own appearance or see what is behind them. However, mirrors in the virtual world are not negatively affected by distance, thus it is possible to see distant objects in high-detail on the mirror, despite this being impossible in the real world. No other abilities are known.
After announcing the rules of the death game on November 6, 2022, Kayaba Akihiko sent a Hand Mirror to the inventory of each player. Then, after requesting them to inspect their inventory to find the item, he forcefully changed the appearance of each player avatar to their real life appearance, based on the data about their real life appearance gathered from the NerveGear. The mirror was meant to be a way for the players to easily see the changes in their own appearance and thus realise that the game had become the only reality for them. After the event, some if not all mirrors were dropped and were destroyed once they hit the ground.