The Catchmaster Rat Wooden Snap Trap 610PE is 3.3" X 6.85" X 1" (L x W x H).
The Catchmaster Rat Wooden Snap Trap usually is not reused especially if a rat is caught. The plastic traps can be reused.
Based on some images I found on the internet, it appears you pull down the square shaped lever of the Catchmaster Rat Wooden Snap Trap 610PE towards the end that has the words Catchmaster printed on it, then you pull down the vertical rod and secure it underneath the black piece on the opposite end of the trap.