- Use this medium hold prep spray for heat-activated shaping and hold. Medium hold prep spray for heat styling. Ideal for curl creation, especially in straight hair. Creates defined hot iron curls. Made with Innovative shaping blend: Polysilicone-9 - thermopolymer for shaping with hot tools, and Polyquaternium-11 – provides additional flexibility. Spray into towel-dried hair, blow-dry and shape with hot tools.