I run one similiar and it is well worth the money. Who wants to carry a ruler on their sled in the field,is a ruler 100%accurate,who wants to hold the cable and try to get a good reading with a ruler,who wants to read the scale on a ruler when eyes are bad,cold out,hands shakey and so on with the list. This tool you put the metal on the end and lay cable in place and adjust for 100% accuracy over and over again. If you do not have the tool at least use a vernier caliper and not a ruler to measure. These tools work over and over again and any inexperienced person can ajust their cables properly and quickly. We spend thousands on the sled and mods but can not affor a $30 tool to set up and have our power valves opening the right lenght for proper performance. Just my opinion and even better yet if you have more than $30 to spend the stm valves or bdx deletes will eliminate having to have a tool period.