Using two bushings together or a bushing and washer(s), you can create a floating bolt that isolates the unit from any metal-to-metal contact.
Different shores allow for different spring rates. Load ratings assume a 10-20% deflection of the material. This deflection is acheived by a combination of system weight and torquing of the connecting bolts.
Do not over torque the bolts as this defeats the intended vibration isolation and shortens the bushings life. Use a high-quality (thread deforming) lock nut or double jam nuts to prevent vibration from loosening bolt.
Unlike other products, busings may be used in tension connections.