Anyone know whats inside of it?
I found this a while ago...
The EVAP canister is filled with granules of an
activated carbon mixture. Fuel vapors entering the
EVAP canister are absorbed by the charcoal granules.
Fuel tank pressure vents into the EVAP canister.
Fuel vapors are temporarily held in the canister until
they can be drawn into the intake manifold. The duty
cycle EVAP canister purge solenoid allows the EVAP
canister to be purged at predetermined times and at
certain engine operating conditions.