What are these plastic parts floating in coolant tank?

[mhowellaz]

For anyone else who comes by with the same question: I visited an indy shop. They said coolant level sensor parts broke loose in the tank. Looks to them like the tank is original, but as good as it looks (not yellowed, no leaks, 15 yrs old), this bit has failed. Gotta watch coolant level carefully until I replace the tank... presumably the coolant level light won't work if this sensor is not working.