Product Liability

I was wanting to know in reguards to bumper fascias and car bodies what type of liabilities are there selling these manufactured composites to end use customers?

If you are making such products what steps, if any, do you take to protect yourself from a law suit?

Aside from business general liability insurance, we carry product liabilty for 1 mil in case any of the products somehow cause damage and they try to blame the manufacturer.
Even with customers signing waivers and such, it’s a good idea to have a policy.

Is product liability insurance expensive? approximate cost for 1 million? You can pm me. I’m just keeping various business avenues open so If I do decide to get into manufacturing car bodies etc.