The length of the bottom extension piece is 135 mm and the locking point
is located at 57 mm to the corner of the sash.
The connection part of extension piece is special designed to allow 2 screws
during assembly. This way the steel cover is fixed properly and safely.
The oscillating part of the bottom extension piece is tensioned with a spring
so you need only one type of bottom extension piece for all dimensions.
Thanks to this special spring, seal pressure is remaining constant which
is a must to prevent water or air leak.