APM Achromat The 7mm-thick APM model, which combines a glass sub-plate and Achromat on top, is designed for Technics turntables such as SL-1200GR . APM's glass is an intentional mismatch against the Technics' metal platter to help control plate vibrations. With the glass controlling the thin aluminum, Achromat now has an inert, stable surface to deliver unsurpassed performance. APM Achromat is not compatible with 1200G or 1500C.