Retrofit kits convert existing pneumatic thermostats to a newer or competitive model when they become obsolete or unavailable. Also known as conversion or replacement kits, they're ideal for buildings with older construction as major renovation is required to update an existing pneumatic system to an electrical one. These kits avoid the costs of conversion as well as the potential health risks and disposal concerns of renovating older buildings. Retrofit kits typically include a thermostat, cover, and mounting and connecting parts. Most kits are brand-specific.