Pneudart that uses 22 blanks and that has a scope on it. There are many cheaper options out there but you will be glad you had one like this in the long run. Pneudart aluminum darts are always in a supply shortage it seems since covid so buy several extra because it takes months to get them direct unless you have a vet supply place that will let you have some until your others come in. 5 darts in a pack including a fill needle to load. If you buy direct and order 15 packages they offer free shipping. 10cc are the largest you can buy for the pneudarts. 7cc and 10cc are primarily what I buy. They aren't cheap. $6 or so a piece. 1/2 inch needle works best for sticking and not bouncing off for cattle. If you need to use much less medicine than what your size dart holds just add some water to it. Green or yellow CCI .22 charges work best. They include a chart for yardage and power charge to be really accurate but you really don't need it unless making a long shot. Most shots can always be be made 20 yards or less but they are capable of shooting much farther if need be.  Extremely accurate but you will find the scope is really nice when shooting a $50 shot and making sure to get a good hit in the neck etc. Put a little neosporin on the dart end to help the gelatin collar slide out easier after the animal's body heat melts it. It also helps the medicine stay in the dart if you should drop the dart or when you turn the gun barrel horizontal. Also you have to use something that isn't too thick of an antibiotic. LA300 and the like is too thick plus takes too much volume. Draxxin and the like usually works much better in the darts being that they are 1cc/100 pounds roughly. About the only thing bad about them is they tend to make your cattle wilder after being shot a time or two so usually its best to use a long acting antibiotic where you are often one and done without a need for retreatment. I doctor 100+ every year out on wheat pasture for pinkeye, limps, foot rot, etc and they are sure convenient for that.