What he said..

I had a Kahles AH 3.5-10x50 with the TDS and it is a really nice reticle. You don't need a rangefinder in order to use it either. Just sight the bullet you will use for hunting at 200 yards. Then shoot at 300 yards and measure the drop from point of impact. You can then find the corresponding sticker and find out the values of each line at a certain yardage. When you use it a few times it will make the job of ranging and shooting animals at extended distance easier but you will still have to put in the range time and shoot a lot at long distance in order to be effective. That is assuming you have the right rifle,cartridge and shootingexperience to take advantage of it.