Exodus 39:35

the ark of the testimony and its poles and the mercy seat;

Exodus 25:17

“You shall make a mercy seat of pure gold, two and a half cubits long and one and a half cubits wide.

Hebrews 9:5

and above it were the cherubim of glory overshadowing the mercy seat; but of these things we cannot now speak in detail.

Hebrews 9:8

The Holy Spirit is signifying this, that the way into the holy place has not yet been disclosed while the outer tabernacle is still standing,

Treasury of Scripture Knowledge

Summary

The ark of the testimony, and the staves thereof, and the mercy seat,

The mercy seat

Bible References

The mercy seat

Exodus 25:17
“You shall make a mercy seat of pure gold, two and a half cubits long and one and a half cubits wide.
Hebrews 9:5
and above it were the cherubim of glory overshadowing the mercy seat; but of these things we cannot now speak in detail.