Easy to use really cleans out the heater core fast.Does what it supposed to doLeaked a little but got the job doneI am a professional mechanic and have actually never had the opportunity to try this tool before until now. I have a Chev Blazer that I physically replaced the heater core on 10 years ago. Well a few months ago it became plugged and I was getting ready to spend a day removing the whole dash board again for the core replacement. I saw this tool on Amazon and figured I really had nothing to lose, but a lot to gain. By the way, you can isolate a bad core by feeling the temp in the two hoses at your heater if accessible. If operating correctly both will be hot when engine is at normal operating. If plugged, you will only have on hot (inlet) the other one (return) will be much cooler or just cold. Okay back to my use of the flush tool...I simply disconected my hoses at the heater at the firewall and install a length of 3/4 to the inlet and 5/8 and the outlet, then installed the Lisle flush tool in the end of the outlet hose and started the "back flush" process. I flushed it with water only in that direction for about 25 min until I had water flowing out at a good rate. So I reconnected my original hoses and topped off my at the coolant at the radiator ( newer cars at the reservoir ) with the engine running and was quite amazed and relieved that it restored my heater core to work like it was new again. I am still amazed at the simplicity of the tool and it's ability to safely clean such a difficult and labor intensive part on my truck. I did not even have to use a chemical additive. I am not so sure that a heater core with extreme sediment build up ( in engines where coolant is not used in a proper mix with water) would benefit from back flushing but it is worth a try, perhaps combining a radiator chemical flush solvent after the initial flushing of the core through the attached temporary outlet hose. After adding the additive let it sit in the core for at least a few hours (follow directions on specific product label) then flush again and see if the flow is restored. Good luck to you.....I hope your Lisle flush tool saves you the time and money it saved me!Used with 5/8 in tubing to flush cooling core. Worked as designed with snug fit.I used this to back flush the heater core on my 2001 Jeep Cherokee. I had little to no heat prior to the flush. This tool worked great. Now I have heat again in my Jeep and couldn't be happier. If you have a no heat issue try this b4 your replace your heater core.If you're buying this you already know what you're using it for. This review is so you know that it fits a 2008 Jeep Liberty just fine.The product is easy to use and it works great. I watched the directions for use on YouTube and then used it to clear my heater core.Really good tool, backflushes never accomplished recovering a heater core until I purchased this tool. I have it hooked up to a hot water line and flush the heater core lines out back and forth until water flows out freely with no signs of any restrictions. I use it professionally and have saved multiple customers hundreds of dollars so far.Super simple. Does the job. Went from a heater core that didn’t heat the vehicle at all to like it was brand new again after using this tool.The stepped design lets you slide the nozzle into any size hose. The trigger allows for a controlled pressure, making this the perfect tool.It worked excellent. I went to mechanic who quoted me $1200 to replace the heater core. It saved me a lot of moneygood quality did the job work well