Stepless Spring Clamp For Thermal Cycle Applications, 3.125 - 3.50 Inch Clamping Range, 0.35 Inch Width

This clamp fits hoses with an outer diameter between 3.125 and 3.5 inches.

Silicone hoses are exactly what this clamp was built around. The installation torque requirement is intentionally low, which keeps you from stressing or damaging the hose material during tightening. You tighten the screw until the spring is fully compressed, then add three more full turns. At that point there should be a small gap of at least 1/8 inch between the two D-Nuts, which tells you the torque is right and the hose is not being overloaded. The torque range is 12 to 18 lb-in, so nothing excessive.