Uses as accurate reference clocks in ATE systems and as in-house frequency standards may be found for the Model 908 and 909 frequency standards. Model 909 includes an ultra-stable Rubidium timebase, while Model 908 is built around a highly stable, oven-controlled, SC-cut crystal oscillator. Both provide five buffered 10-MHz outputs plus one 5-MHz output. Option 70 increases the number of 10-MHz outputs to 10.Thanks to its negligible aging drift, Model 909 needs practically no adjustment during the lifetime of the test system. Model 908 is said to offer the lowest purchase cost per output on the market in the 11-output version (Option 70 installed).