You focus your powers of observation on an iron-plated solenoid:
Item 'an iron-plated solenoid' is type light, alignment 0, made of iron (in (new) condition),
has keywords 'heavy iron plated toroid solenoid crackling'.
This item weighs 0 stones and 99 pebbles, and is valued at 28,600 gold. {Cat. 9}
This level 240 item has the attributes: no-sac no-auction magic-resistant will-float
* This light source will last indefinitely.
Affects spell-points by 100.
Affects hp by 47.
*Your level must be greater than or equal to 240 to use this item.
*This item may be repaired 1 time.
This dense, heavy donut-shaped mechanism levitates about you, emitting a
hum like a low rumble, almost too low to hear, to the point of simply
emitting sonic shockwaves as it dances in the air above your head.  Coils of
electricity ripple and screech across its surface, occasionally arcing
across the round divide partitioning one side from the other, snapping the
air viciously.