The device is found by the keywords “Dakota Weather Station Clip”. It has a battery holder for a coin cell, which can be opened/closed with one such cell (or a fingernail unless it’s too tight). It’s convenient but adds thickness to the device, most commonly a bike speedometer. It is featured on Wikipedia’s list of screw head types (linked by OP) although most such covers don’t actually screw in, they latch after a small rotation. This seems to be one of them since there’s a triangle marking the latch position (albeit useless without a corresponding label on the device).
I’ve seen ones where the clip has been clearly forced with a small flathead screwdriver. If you have one (or a piece of cutlery, ballpoint pen core, twig or something), insert it sideways instead for more torque without damaging force!
The device is found by the keywords “Dakota Weather Station Clip”. It has a battery holder for a coin cell, which can be opened/closed with one such cell (or a fingernail unless it’s too tight). It’s convenient but adds thickness to the device, most commonly a bike speedometer. It is featured on Wikipedia’s list of screw head types (linked by OP) although most such covers don’t actually screw in, they latch after a small rotation. This seems to be one of them since there’s a triangle marking the latch position (albeit useless without a corresponding label on the device).
I’ve seen ones where the clip has been clearly forced with a small flathead screwdriver. If you have one (or a piece of cutlery, ballpoint pen core, twig or something), insert it sideways instead for more torque without damaging force!