Improvised Explosive Devices
From the TV series ARROW
The 2 background devices had mobile phones attached when they appeared on-camera, and featured flashing LED "ARMED" indicators.The foreground devices were conceived to be set to detonate shortly after being armed, and were intended to be thrown like a hand-grenade.
Lifting the switch-guard, and pressing the revealed pushbutton, started the timed interval (and caused an integrated LED indicator to flash).