Very low and affordable rails with nice finish.
The Norsap Basic Rail needs a flat and rigid surface to prevent the wagon from blocking up because of bending of the rails.
For seat NS 800.

recess depth: 14 mm (not surfaced mounted)
protruding height: built in, 0/38 mm
: surface mounted, 15/52 mm
width of rails: 444 mm (excl. surface mounted trim)