Schoen Insulation Services | Manufacturing of Non-Metallic Machined Parts SIS, an EIS company, is the national leader in the manufacturing of low-cost machined, cut, turned, & assembled parts. Our commitment to quality, service, and competitive pricing has expanded our busi SIS, an EIS company, is the national leader in the manufacturing of low-cost machined, cut, turned, & assembled parts. Our commitment to quality, service, and competitive pricing has expanded our business worldwide. Our full line of manufacturing equipment coupled with our highly qualified and professional staff are ready to meet your most complex needs.