From the Anvil Gothic Thumblatch

The thumb piece passes through the door and raises the latch bar off the keep. To restrict the latch bar movement a staple pin and screw-on staple pin are provided (discard unused pin). For use on doors with a maximum thickness of 55mm. DIMENSIONS: 216mm Handle Length 140mm Thumb Bar Length 190mm Latch Length FINISH: Beeswax Black Pewter

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