Sierra Shields Nautiflex Silicone Exhaust Hose 2-12 Sierra Shields Nautiflex Silicone Exhaust Hose has a blue silicone cover w smooth finish for easy clean up. The Nautiflex hose is flexible, easy to install and has four piles of synthetic fabric and remains stable at elevated temperatures. Specifications I.D. 2 12 or 63mm O.D. 2 78 or 73mm Wt. C 82.6 The temperature ranges from -20F - 350F Meets SAEJ2006 Type R1 and ISO 133632004 - Type 2 - Class B standards Applications Primarily used for stra