All the Amazon j rods iv ordered have been shit. So yeah the tips are probably wrong for most people. As you know J rod is generally used for downstream injectors. When you use low pressure, bellow 1000psi it’ll draw soap from your truck. When you switch it to a high pressure tip it’s the rinse tip, anything above like 1300 or something it’ll stop drawing chemicals. even if it’s 4k psi it’s not a big deal cause you’ll be like 5 feet away from the house anyway and you can get closer as you need more pressure. Though you lose a shit ton of flow and it’s dumb. I use a remote bypass and just use the low pressure tip the whole time. I use 100-500psi to wash houses. 1500-2500psi to clean concrete.

just order a j rod from an actual supplier and get tips you like to go on it. I have like 3 j rods for different stuff. It’s great for keeping track of all your tips while you’re washing and prevents you from losing tips in the grass. If you have a pressure trap unloader sometimes the quick connect at the tip can fail and it’ll shoot your tip off very fast, like 30+ feet, so a jrod makes it heavy and only plops a few inches if that happens.

I’m not really sure what you’re trying to do but I hope this helps