Single Manual control and 7 day timer. Stroke length is manually adjustable, stroke frequency is fixed. In timer mode, pump is controlled by 7-day programmable timer. 10:1 max turndown. Pulsafeeder PULSAtron PLUS Series T7 chemical metering pumps are positive displacement, diaphragm type pumps with Integrated Feed Control with 7-Day Programmable Timer. Output volume is adjustable while pumps are in operation from zero to maximum capacity.