Wis. Stat. § 895.448: Safety devices on farm equipment, ordinary negligence.

(1) In this section:

(a) “Farm equipment” means a tractor or other machine used in the business of farming.

(b) “Safety device” means a guard, shield or other part that has the purpose of preventing injury to humans.

(2) If a person in the business of selling or repairing farm equipment fabricates a safety device and installs the safety device on used farm equipment, after determining either that the farm equipment was not originally equipped with such a safety device or that a replacement is not available from the original manufacturer or from a manufacturer of replacements, and notifies the owner or purchaser of the farm equipment that the person fabricated the safety device, the person is not liable for claims founded in tort for damages arising from the safety device unless the claimant proves, by a preponderance of the evidence, that a cause of the claimant’s harm was the failure to use reasonable care with respect to the design, fabrication, inspection, condition or installation of, or warnings relating to, the safety device.