Explosives are fit into a normal pen or phone, or other object. A person who picks it up is, at best, crippled.
"In all the time of our stay here, we have neutralized several hundred of such surprises. We encourage people not to pick up anything that doesn't belong to them. Even if you see an expensive phone or something like that on the road. Better leave it. Besides, if you see an abandoned bag or a case or an unknown car that has been parked near your home for a long time, just call the Ministry of Emergencies. This way you'll save your life and others near you," Serhii Holoborodko said.
For better example, the Ukrainian military sappers even organized a kind of exhibition of "surprise mines" (booby traps).
Photos courtesy of the ATO press center