DNAngel Exhibition Notice Letter Set by Triball was originally released and sold at the DNAngel Exhibition held at the Marui City Store in Yokohama in May 2021, and later released on the Marui Web Channel's online anime shop for mail order, as well as resold at the other exhibitions. This letter set is themed after the main character Dark Mousy, and includes 4 envelopes and 8 cards featuring the illustration on the cover of DNAngel New Edition Volume II in the background and look like his signature heist notices, along with 4 sticker seals with different logos on them. It was created to commemorate the completion of Sugisaki's long time and internationally beloved manga work after 24 years.