I bought this product to be useful when I do a drain and fill on the various fluids, such as coolant, power steering fluid, and brake fluid in my vehicle.
Using this tool to drain and fill rather than just bleeding the lines comes in handy not only because it is a lot quicker, but it makes sure that air doesn't get into the lines, which could damage your vehicle.
Most people only assume that oil and transmission fluid need to be changed, but usually forget about the other important fluids, which can lead to wear of the various parts and overall failure overtime.
With this tool, when I hit my 40,000 mile mark, I was able to use it to suck out all of the fluid in my PSF reservoir, and refill the reservoir to the max mark with the appropriate PSF for my vehicle. I then started the car, and rotated the wheel lock to lock slowly, about 5 times each. Then I got out and repeated about 5 more times until I emptied the entire 16 fl oz bottle of psf through the system.
The drain and fill essentially cleans the fluid that is already in there...by taking out old fluid, then mixing in new fluid, the ratio of old to new fluid changes, essentially making the fluid cleaner and cleaner with each drain and fill.
Now when 60,000 miles comes around it will be time to D&F the coolant. At that time I will only have to suck out all of the coolant in the coolant reservoir and refill it.
Overall, this product is a great tool to help with your automotive needs.
It is a pretty solid metal body, and it all comes apart for easy cleaning.
The only problem I have with it is gravity. When you finish sucking up fluid, the residual fluid that didn't get sucked up into the pump, but only in the tube, will flow back out slowly, so just be careful not to spill any fluid, especially on the power steering belt, because then it would slip.
This product is an AMAZING DEAL for the price. These products go for about 30 dollars.
I suggest getting one if you are an experienced DIYer.
I give it 5 stars for its sturdy solid metal construction, the price, and the fact that it does what it is supposed to do.