Marklin 24430 - C-Track Curved Track, R-4, 30 degrees

Radius R4 = 579.3 mm / 22-13/16". Curve 30°.

Parallel curve to Radius R3 with a spacing of 64.3 mm / 2-9/16". 12 sections of track form a circle with an outer diameter of 120 cm / 47-1/4"

Also sold in box of 6 under 24430-1

Read Charlie's blog on C-track curves