The tool is different than pictured. As other reviewers have said, you need to drill a small hole in the tool to make it work properly. The tool does what it’s meant to do, and necessary, unless you fabricate your own.
See my pictures of the tool that you will receive. Talked to Walker Evans, and this is the 'new' version of the tool. They said that they hadn't heard of the hydrolocking issue, but I wonder if they have even used it. Mod (small relief hole, 3/4" from end) is definitely necessary, otherwise you won't be able to screw on to the IFP in oil (fluids are incompressible).
Like the other reviewer said I had to drill a small relief hole in the bottom of the tool because it create an air lock once the tool is screwed onto the IFP. Also not exactly as pictured but it did the job. I rebuild all 4 WE shocks on my 2014 XP 4 1K in about 2.5 hrs.
The tool I got did not look like the picture but was designed for my shock repair. Had to drill small air relief hole 3/4" of an inch from threaded end. When screwed onto floating piston a air lock was created and piston could not be pushed down, even when only screwed on about 3 threads.