EVA foam Tubes.  Super high quality.  Easy to sand and shape.

Number 1-5 are 17 3/4" x 1.18" x 3/8” nominal Number 6-10 are 17 5/8" x 1.18" x 1/2" nominal Number 11-15 are 18" x 1.25" x 3/8" nominal.  The solid tubes are 45 degree hardness and the rest are 60 degree hardness.