Proper Tools To Measure Pulse Rate

My father ask my help if where we could find good pulse measuring tools that he will use when he spend a mountain climbing. I told my father that better if we can purchase an oximeter. This kind of device is being use now by several mountaineers. We can find good guides and reviews from expert on how we can use this kind of device. For me I prepared to use a proper oximeter in measuring my pulse. This device is the best way to measure our pulse rate at the present.