Used in counting bacteria colonies that are presented against a dark background, this counter has a built-in electronic register operated by standard needle-point probe, or by optional push-button counter or marking pen probe.

Illumination is provided by 40W tungsten bulbs. The 113mm lens offers 1.5x magnification and is positioned to eliminate parallax errors. Focus lens by sliding rod; swing away when not in use. Second optional lens may be attached to increase magnification to 3x.

The counter automatically records as you count. When the ground and counting probes both touch the conductive agar in an open dish, an electrical circuit is completed through the integral amplifier, which activates the digital counter. A reset bar provides immediate zeroing of five digit counter. Sheet metal case is finished in contrasting gray-beige acrylic enamel and black suede. Dimensions: 26.7Lx27.9Dx25.4Hcm (10¹/₂x11x10").