3M Diamond Grade DG3 Reflective Sheeting Series 4000 features the most efficient retroreflective prism design currently available from 3M for use on vertical traffic control signs and delineators to return light to drivers under a diverse set of nighttime viewing geometries encountered by the driving public. Series 4000, as manufactured by 3M (“Sheeting”), meets the stringent retroreflective requirements given in the ASTM D4956-16 standard for Type XI retroreflective sheeting.