Electromechanical Impulse Counters 6 digits standard counter allows registering of one million operations Available in 3 standard voltage ranges - 6 V DC, 12 V DC and 24 V DC, Good performance at speeds upto 5 impulses per second. Counter speed: 300 counts per minute, Digit material: Poly Acetal Co-polymer, Character colour: Digits in white on blue on blue background.