I build a product that requires well-aligned threads. Hard to obtain with a standart T-handle. This device increased my production speed by a factor of 2. It is finicky and requires some experience to use correctly. First, the flat head set screws in the tap adapters have a flat head set screw that must be thrown away. Get a hex head set screw. Second, adjusting the counterweight is a painful process. Very handy when it works well. Total pain when it does not. The loose vise on the bottom is helpful to align. Turn the tap backward and allow the material to align, then go forward. There is enough leverage in the handle to easily snap any tap, followed by a flurry for 4 letter words and a trip to the hardware store. MUST be bolted to a solid table for any rational use.I bought these for my Lassy 12-F hand tapper. About half of them fit my Lassy holder (quite snug), and about half had diameters a couple of thousandths too large. My Lassy tap adapter holder is old so I took a chance and reamed it with a 0.747" reamer - now all the HHIP fit nicely and so do the few original Lassy adapters I had. I realize this added several thousandths of an inch play in some of my tap holders, but I'm not doing any work that requires that level of precision. These are clearly Lassy clones, but you may have to polish the adapters down or slightly enlarge your Lassy holder to use them. Also, unlike my original Lassy tap holders, these are not labeled/marked clearly - the ends are a bit rough and black, so the size stamped on the ends is hard to read.One of the most important parts of this thing, the tap holder/chuck doesn't lock the tap in place. No matter how much pressure you put on the tap body, it slips. Now I'm looking for an alternative so that I can install the tap and use this thing.wrong fit for my tapperDid not come with assembly instructions just an exploded parts diagram. Once figured out, it is so much easier and faster than using just a tap handle. I found it best to remove one handle so as not to whack my arm as it turned around. A small wheel with a handle would be ideal.These things are too loose so they don't hold the tap straight when you tighten the set screw. JunkCheaply built. Retaining screws for collects are terrible had to rplacee. Roller on end of counter balance was seized up out of the box. Retaining pin loose fit and don't hold. Do not buy this product. I'd give it a 0 star rating if I could!Great tool for the money!Handy tool for odd taping jobs in steel or hard to machine metals. Mine came damaged, but amazon was able to help slightly. Im trying to get replacement parts from HHIP but they are difficult to deal with.El producto funciona a la perfección, además de que está elaborado con material de larga duración y calidad en cada milímetro cuadrado.