hitachi magic wand
An electric clitoral vibrator. It looks like a strange microphone with a white and/or gray head that vibrates.
The Hitachi Magic Wand was originally released in the 1970s as a therapeutic muscle massager, but was quickly picked up and utilized as a sex toy. In 2013, Hitachi ceased production of the device over concerns with the Hitachi name being associated with sex toys. However, production was later restarted, with Hitachi dropping its name from the product. The device is now distributed by Vibratex, under the name "Original Magic Wand" or "Magic Wand Original".
Its Pixiv tag is 電マ (den-ma), an abbreviation for 電動マッサージ機 (electric massager). Not to be confused with denki anma.