Have to agree with Oldtimr knowing your range is very important in archery. Even if you site in at a range trying to guess distance while hunting is very hard. A few years back I got permission from a farmer to hunt deer bothering his yard. It was a great oppertunity the first deer I saw was eating hay right by his corral. So I walked down the fence got to the end of the fence there is the deer at what I thought was 30yds. Easy shot that is my first pin and I shoot and miss. I quickly get another arrow and assuming I had done something wrong concentrate and shoot again another miss. Load another arrow but this time use that thing hanging around my neck and range oh he is 40 yds sure did not look like it. The deer ran off unscathed laughing all the way. The tuth is I actually really thought the deer was may 25yds wich is what my top pin is set for. Long story short spend the money and get a range finder. Maybe spend the extra coin and get one the gives actual horizontal distance not just the angle distance. This can help if hunting coulee's or even in a tree stand.