In the beginning of SAW Part 1, what is the thing that goes down the bath tub drain that Adam is in?

I'm going through each movie over the next few days trying to get everything straight before seeing part 5.In the beginning of SAW Part 1, what is the thing that goes down the bath tub drain that Adam is in?
It's a key to his chain.





Remember at the end of the film the ';Jigsaw'; character says,





';The key to that chain is in the bathtub';In the beginning of SAW Part 1, what is the thing that goes down the bath tub drain that Adam is in?
Yep the other people before me got it, It was the key to unlock himself, the lightup thing was so he could find it in the dark
Its the key that could have gotten him and the other guy out of the chains. That key could have saved their lives.
the key to the lock
the key to the lock that will let the guy out of the chain
it is the key to the locke of the chain to which he is tied with
Its the key of his lock..
the key that would of unlocked his chains
His key!
what they said ^!

wrinkles