According to information of a professional for altitude training and hypobaric therapy all pulse oximeters +/- are equally good. Therefore, and as several reviewers have already assessed in detail the PO-300, I only say that values are plausible and stable even during training on an ergometer. Rattling with the PO on the handle of the ergometer is however actually prohibited. Importantly, and as I have found different information in the reviews, the trouble-free installation and use of SPO2 program is compatible with all modern Windows operating systems: The software installation SPO2 Assistant V1.5.0 is simple (requires restart). I have 7 32 / tested the functionality under Windows 8.1 64-bit and 64-bit Windows. The important thing is that the PO will be taken only after starting the program in operation and that USB is enabled on the PO. Otherwise in the Device Manager (when plugged PO!) Check whether the Silicon Labs USB to UART Bridge CP210x is (under Ports (COM & LPT)) installed correctly. An update can be found at [...]. The Dremel USB cable is 1.5 m long and has to be used, but the length is sufficient to provide a laptop next to the ergometer. The use of a USB extension cable is possible, but not the operation via a USB hub. In the operating instructions the indication of capacity and charging time of the battery is missing! However, the charger turns off when the battery is fully charged (blue pilot light goes out). I'm very curious to see if the battery does exchange for his life, or if the problem is "planned obsolescence" and this PO concerns ... A protective cover is not enclosed. The acquisition should be considered.