 Specification writing is often a distinct professional trade, with professional certifications such as "Certified Construction Specifier" (CCS) available through the Construction Specifications Institute and the Registered Specification Writer (RSW) through Construction Specifications Canada.Specification writers are either employees of or sub-contractors to architects, engineers, or construction management companies.Specification writers frequently meet with manufacturers of building materials who seek to have their products specified on upcoming construction projects so that contractors can include their products in the estimates leading to their proposals.