Thomas1030 ABS Plastic Traceable Digital Stopwatch with 25/64" High LCD Digits, 0.0005 Percent Accuracy, 3" Length x 2-1/2" Width x 3/4" Thick

This is a well-made stopwatch with only basic functions. I like the feel of the buttons, and the case really does have a rubber gasket for water resistance. The beeper is not too loud and sounds whenever you press (START/STOP) or (SPLIT/RESET) but not when you press MODE.The manual is well-written. It recommends replacing the battery with a 1.5V, 357 type silver oxide battery, but it ships with a Golden Power brand LR44G, which is an alkaline battery of the same physical size.The unit I bought came with a calibration certificate that indicates a loss of 0.167 seconds over 24 hours, which is accurate to 1.9ppm and well within the specified ±5ppm tolerance of the device. The unit was calibrated on 2017-09-28; I purchased it on 2018-09-02, and it is due for calibration on 2019-09-28.The crystal inside the stopwatch is a can-format tuning fork crystal. I am guessing that this unit is not temperature-compensated because the crystal is not physically close to the control chip. Furthermore, the calibration certificate states, "In our opinion, once calibrated your Digital Stopwatch should maintain its accuracy. There is no exact way to determine how long calibration will be maintained. Digital Stopwatches change little, if at all, but can be affected by aging, temperature, shock, and contamination."For the curious, the Citizen CFS-20632768HZFB watch crystal is specified to ±5ppm initial tolerance, ±3ppm first-year aging, and -0.028 to -0.04 ppm/°C² temperature coefficient. I don't know if this stopwatch uses that crystal, but it is specified similarly.

The media could not be loaded.  I bought this for technicians at my lab to use expecting it to be very high-quality and last a long time. This has only lasted three months, and it is not just a dead battery. I have replaced the battery and no change at all. Would not recommend.