A Thybar Multi-Zone Retro-Mate®is custom-made to adapt the existing curb and zoning to the new rooftop units. It saves time and costly roof reconstruction, preserves roofing integrity, reduces system downtime, andtakes advantage of existing ductwork and zones. Thybar's library of new and old rooftop specifications allows us to design a matching Multi-Zone Retro-Mate® without expensive fieldwork. Reduced engineering and construction time lets you bid more competitively. Direct inquiries to www.thybar.com. Thybar Corporation, 913 S. Kay St., Addision, IL 60101. 800/666-CURB. Fax: 630/543-5309. Email: info@thybar.com. Website: www.thybar.com.