Many normal worm-drive clamps will cut into the softer rubber of aftermarket silicone radiator hoses. This can cause the clamps to bind up and fail to seal the hose, resulting in a coolant leak. These special clamps have a special coated screw section, and a smooth underside that won't catch on the silicone, reducing the chance of a bad seal and increasing the life of the hose. Sold as a set of six clamps, sized properly for your Subaru BRZ / Scion FR-S radiator hoses.