From the Anvil Beeswax Gothic Thumblatch XL
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).
Comes with an extra long thumb bar for use on doors with maximum thickness of 75mm.
216mm Handle Length
170mm Thumb Bar Length
190mm Latch Length