From inside (document excerpt):
V-1550 MultiMatrx® Series Sprinklers 5.8-16.8m (19′-55′) Radius Features · Adjustable-flow nozzle, 3.2-44 LPM (0.85-11.62 GPM) · Full-circle and adjustable partcircle (40°-360°) models available · All adjustments made from the top wet or dry · TruJectoryTM adjustment from 7° to 25° for fine-tuning nozzle spray trajectory · Smart ArcTM memory maintains previously set arc and minimizes vandalism · Balanced precipitation rates · Standard rubber cover (except shrub models) · Servi-SnapTM snap-ring design for easy servicing · Proven planetary water lubricated gear-drive design · …