Quick Summary: MSTE users who don't have an MSTE - get this mouse as it's the closest "replacement" to date. Obviously, if one wants a mouse like the MSTE, then get an MSTE. But even a used MSTE costs a bit and you have to be careful of the cord. If one wants something Less Expensive that closely resembles the MSTE and is also cordless, then this is the best mouse on the scene since the MSTE itself.Update2: Trying to add some slightly better pictures and others that show the MS Trackball Explorer, Logitech Cordless Optical Trackmall, and the smaller Elecom "DEFT" trackball mouse. But some pictures are not loading to the site. Sorry. :(Update1: IMPORTANT NOTE: Waaay down in the comments (the oldest one at the "bottom" should be a link to the Elecom software download page and the English PDF manual. As this mouse is "very new" you *DO* need a more recent Elecom proprietary software to recognize this mouse if you wish to use it's three proprietary function buttons (F1-F3).Long Winded Review===============This new Elecom Fingerball wireless mouse - the M-HT1DRBK - appears to have been released is June 2017 and has been available on Amazon since July 2017. In August I was about to order a second of the smaller Elecom M-DT2DRBKs when I stumbled over this new **larger** "HUGE" mouse and figured it was worth a try. The M-HT1DRBK just arrived and after giving it a ten minute test spin I just ordered two more. No clue if it will take "1-2 months" for the next batch to arrive, or if the price will drop from $85.99, but would say it is certainly worth the investment. FYI: It actually does say "HUGE" on the mouse itself. :)Comparisons to the MSTE (MS Trackball Explorer)======================================1) It has a nice large "red ball" like a certain MSTE we all know and love. In fact, the Elecom ball is slightly BIGGER than the MS one. There were many reviews about the smaller Elecom mouse's "grey ball" having issues, and several people purchased a "blue" M570 ball to swap with the "grey" one. From my quick tryout of this new mouse with it's "red ball", would say that the quality looks to be significantly better than that of the smaller mouse's "grey" one. An excellent improvement.2) This mouse is *MUCH LARGER* than the smaller "grey ball" M-DT2DRBK. Excellent for people with "larger" (aka normal sized) hands.3) It is a bit wider than the MSTE, and Elecom moved one of the three proprietary "Function Buttons" to the right side of the ball. If you use their proprietary software, this would give you "two buttons to the right of the ball" just like the MSTE.4) MOST IMPORTANT OF ALL. This mouse has a PALM REST. As this seems to be an alien concept to most mouse manufacturers I will state it again - this mouse actually has a place for the palm of one's hand to "rest" while using the mouse, so for the first time since the MSTE, there is actually a trackball that not only fit's one's hand, it is actually COMFORTABLE. Plus it doesn't have teeny tiny thumb-killing buttons like a certain L*git*ch Trackman. Wish I could show a decent side-view of the palm rest, but this can also be seen with via the pics on Elecom's web site.5) ??? I would assume that being a wireless device, there may be an occasional "lag" in response times, but cannot say for certain. However there does appear to be a wired version of this mouse as well. It's part number (August 2017) is M-HT1URBK.Usage=====Bulk of this review was written after only ten minutes of mouse use, so haven't had the time to give it an extended run, but observations so far are positive. "Weeks later" - Still great. Haven't tried the Elecom software yet myself (not using the F1-F3 buttons).- Seems to respond MUCH better than the smaller Elecom version (blue or grey ball).- Range seems to be about the same as the smaller one. About nine feet out it gets tricky and Line of Sight is critical.- The "left" button isn't as "tall" as the MSTE's, so my clumsy thumb is hitting the wheel, but this should be a minor issue.- ??? I read elsewhere that the "left" and "right" mouse buttons are "better quality" than the other buttons, that one should be able to tell the difference, that they should have made *all" the buttons "better quality", etc. Haven't noticed any difference between buttons yet. Too busy enjoying having a wireless mouse that actually fits the shape of my hand for a change.Customization - aka The Buttons========================So far as remapping buttons, "drivers", and support for various operating systems... Would assume this mouse works as a basic mouse in anything from XP up to Win10. You've got your Left, Right, Forward, Back and Wheel Buttons, plus the three Extra Proprietary Function Buttons F1-F3. Remapping the eight buttons and basic customization is where it gets interesting. Would assume one needs at least version 5.1.0 of Elecom's proprietary software to use/control all eight buttons. For now I am sticking with X-Mouse Button Control which allows configuration of everything except the three extra Function Buttons. Both programs allow for the use of multiple profiles for easy customization across different applications. Elecom's software (and English PDF manual) is available from their website. I will try adding possible links as a "comment" later as this review is too long as it is.Odd Future Issue (?)================Since the palm-rest is made of a "soft" material vs plastic, I wonder how it might hold up over time. Will it wear out? Time will tell.