It had been rumoured that Keeler intended to introduce a rival contact applanation tonometer to the market where for decades the Goldmann had ruled unopposed.
I recently got my hands on one and have to report that to all intents and purposes, I cannot find any difference other than in name.
The basic unit (Figure 1) may be used on the usual baseplate or attached to an overarm on the slit lamp (Figure 2). It uses a standard prism cone (Figure 3) and is available in a student-proof case (Figure 4). Calibration is the same (Figure 5) and, if the instrument is stripped down, it has the same system of springs and levers that control the force of the arm (Figure 6, front and Figure 7 back view).
It seemed robust and comparable in use so the choice has to be a more commercial one. ?